the crucial bit are these chains which encircle the rod, one, and here is a second -- and entwine. this is the double helix. an extraordinary feat of intellectual deduction, and it led to a whole new branch of science -- molecular genetics. more recently, dna has given us new insights into the family relationships of animals using a technique called dna fingerprinting. it was developed by sir alec jeffreys of leicester university in 1984, and using just a simple smear of blood, it's possible not only to identify one particular individual, but to establish whether or not it's closely related to another. for example, we used to think that most birds lived in straightforward pairs. we watched them courting and mating and rearing their young, and so we assumed that they were faithful to one another. but dna fingerprinting showed us how wrong we were, as i explained in "the life of birds." perhaps the most bizarre behavior of all takes place in the suburban gardens of england and it seems that until very recently nobody even noticed. a young female hedge sparrow a dunnock, ready to lay. this is her mate, alpha, singing lustily, declaring his ownership of the nest and the territory around it from which he gathers food. the pair often feed together a devoted couple if ever you saw one. he seldom lets her out of his sight for she is not as faithful as she might be. there's a third bird around, beta, another younger male. he's not popular with alpha, and they're continually squabbling. sometimes the fights can get quite vicious and feathers fly. but in spite of that beta stays around, skulking in the hedge. alpha, it seems, has the female to himself once more but she has got her eye cocked. beta is still in the hedge, calling quietly to her. she joins him. and now, while alpha is preoccupied with feeding she and beta get together. twirling her tail is an invitation and in a split second they mate. beta flies away. but now, out in the open, she is courting alpha with that same old tail twirling and now he mates with her. she has kept two males happy both of whom will help to feed the young when they hatch. dna fingerprinting has now revealed that only about a fifth of the apparently monogamous birds are actually genuinely faithful to one another. molecular genetics combined with long term studies of animals in the wild have challenged our preconceptions about how animals live their lives. and there are also long term studies that have shed light on our own evolution and ancestry. in particular, those by jane goodall, who started her work in 1960 in tanzania on chimps. the 26-year-old jane goodall arrived in africa with no scientific training, and had to patiently follow the chimps for two years before they allowed her to get close to them. in order to identify them, she gave them the sort of names we use for one another -- which got her into a lot of trouble with more conventional scientists, who accused her of crediting her animals with human characteristics for which there was no evidence. but she made some revolutionary discoveries, including proving that chimps use tools and even modify them for particular purposes. they fish for termites with twigs which they make more effective by stripping off the leaves. manufacturing tools in such a way had, until then, been thought to be something that only human beings could do. but in the late 1970s, chimps on the other side of the continent in west africa, were discovered using different tools in a different way. placing the nuts in a hole in a root, they crack them open with specially selected hammers. repeated use has deepened the hole and produced an anvil that holds the nut in place. using these tools, experienced chimps can crack two nuts a minute. for the hardest nuts they keep and transport rare stone hammers. cracking is not easy -- you have to choose both a good anvil... and a good hammer. only west african chimpanzees have developed this nut cracking ability and it takes more than 10 years to learn the technique. it's now known that chimps use up to 20 different types of tools. nut cracking was first discovered by christophe boesch, who had been studying these chimps since 1976. and in 1989 i went out to the ivory coast to visit him. how did you manage to get these animals so accustomed to you so that we could stand as close to them as this. oh, just patience, took us five years. five years. five years just following them, being always very quiet never aggressive. always the same colors and clothes, and patience patience. attenborough: but christophe wasn't entirely sure that he wanted a 63 year old with him in the forest. "who is this old man," he said, "who is this old man who wants to come? is he fit, can he run?" the answer to those was no on both, but nonetheless, i managed to get there. and his technique was that he would travel with them all day wherever they went and when they moved he moved. and he didn't leave them until they had made their nests at night. and only then would he go back to his camp, but then get up at 4:00 the next morning in order to run back there to catch them before they went off again. and he was quite -- christophe was quite right. i mean it's hugely demanding. i've never been so tired in all my life. but christophe had also discovered a darker side to chimps' personalities. you don't normally think of them as hunters more as gentle vegetarians munching fruit and picking leaves. but if you follow them for any length of time in their true home these forests in west africa you discover that they are hunters. what's more, they hunt in teams and have a more complex strategy than any other hunting animal, except -- [ chimps squawking ] except, of course, man. the technique they'll almost certainly use is that one of them will be driving the colobus ahead of him then there will be others that go up on either side who are the blockers who won't make any attempt to catch the monkeys; and then there are chasers who go and grab at the monkey if they can; and finally there's one male who will go up ahead and ambush it, so bringing the whole trap closed. the monkeys are now getting alarmed. a driver's going up to prevent the group from settling and to drive them towards an area where they're more easily trapped. now, it looks as though they're all in position. the drivers have gone up the blockers have gone up, and now the one who's going to make the ambush and close the ring he's gone up, too. the colobus will be very lucky if they escape now. [ calling, squawking ] they've got one. and now the kill is brought down, so that the females and others can share it. and there's the reward for that long chase, the divided body of a colobus monkey. these blood-stained faces may well horrify us, but we might also see in them the face of our long distant hunting ancestors. and if we are appalled by that mob violence and blood lust we might also see in that, too, perhaps, the origins of the teamwork that have, in the end, brought human beings many of their greatest triumphs. but the studies of chimpanzees started by jane goodall, continued by christophe boesch and others have shown us something else. it's not just that chimpanzees are capable of developing their own techniques for hunting or tool making but that each community of chimps is capable of developing its own version. in other words chimpanzees' communities have their own cultures, and that was thought to be something that was uniquely human. everyone knew, of course that chimps are our biological cousins but it's only in the last 20 years that we've discovered that we share about 95% of our dna with them and that's because we now have the tools to find out exactly how closely we are all related. in 1990, scientists in 20 labs around the world set out to identify all the 3,000 million separate chemical units that make up the human genetic code. it took nearly 13 years, and then, exactly 50 years after crick and watson had worked out the structure of dna the human genome was cracked. and this is it. in these volumes is all the information needed to define the genetic structure of the human species. each number refers to one of our 23 chromosomes. if i open it up, you can see that the text consists of just one very, very, very long list of just four letters -- a, c, t, g. each combination represents instructions for one element in the human design. this is the secret language of dna -- this is the book of life. and each one of us has our own edition. when i first heard back in 1953 that the structure of dna had been worked out, i could scarcely have imagined that it would ever be possible to print out the whole of one genome in a book. but today the process has been so speeded up that it's possible for anyone to have it done in half a day. and the comparison between the genome of one species and another has proved very revealing. the hot chemical springs of yellowstone contain the very simplest form of life -- single-celled bacteria about as far removed from our complex selves as any organism could be. but we share some 200 of our genes with those very early life forms. indeed, there are some genes that are common to every single species of life on the planet. our dna extends in an unbroken chain right to the beginning of life 4,000 million years ago. so, now we can trace our evolutionary heritage back through geological time. back to the age of dinosaurs... and further still, to the early amphibians. back to the fish... and the first backboned animals. and further still to the single-celled organisms that were the very earliest form of life to appear on this planet. so, in my lifetime, science has solved many of the riddles which, 60 years ago, seemed so baffling. how mountain ranges are formed why animals are distributed in the way they are and how they communicate with one another how a complex chemical molecule can transfer the characteristics of one generation to the next. so, now, the natural world makes more sense than it ever did, which is why studying it is so rewarding and so delightful. over the course of attenborough's career, we've seen wild spaces disappear, and wild creatures vanish. attenborough: we became witness to a slow-motion tragedy. but in the past 60 years we've started to reverse this trend. attenborough: we realized that true conservation means protecting the entire habitat. and now, despite the damage we've done, there is cause for hope. don't miss a single moment. now you can watch "nature" online. go to pbs.org to screen complete episodes from this season and seasons past. visit "nature" online for production updates from the field. well, here we are on the alaska coast. go behind the scenes with our filmmakers. we also used a borescope lens and that allowed us to put the lens right into a flower. and get connected with "nature's" online community. all at pbs.org. "nature" is made possible in part by... leave it untouched by your presence capture its image and preserve it forever. canon -- living and working together to appreciate today and care for tomorrow. additional funding for "nature" is provided by... the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. to order this three-part "nature" series on dvd and blu-ray call 1-800-336-1917. to learn more about what you've seen on this "nature" program, visit pbs.org. available now on shoppbs downton still stands. i'm looking forward to all sorts of things. what?! no one must know! i'm warning you... to order, visit shoppbs. also available on itunes. 5,4,3,2,1... when you want to go above. it is a major exploratory expedition or reach beyond. it was exciting and mysterious when you want to dive deep. words cannot describe how amazing this is or push the limit i am constantly awestruck... nova. only on pbs. narrator: it is one of the most haunting crimes in american history-- the daring kidnapping and tragic death of charles lindbergh, jr., the precious son of america's then-greatest hero. paula fass: the kidnapping, the death... americans witnessed something truly awful here. narrator: one man, bruno richard hauptmann, was arrested... prosecutor: you took that money from that shoebox... narrator: ...tried, and executed. but was he really guilty? did he have accomplices? and could the crime have been masterminded by someone inside the lindbergh household? john douglas: what we do know for sure is that the baby was put to sleep in that bedroom. narrator: john douglas, america's leading criminal profiler, is on the hunt for clues that could solve this notorious kidnapping. did the police... did they ever do a sketch? robert zorn: they did. and i've shown this to hundreds of people, and they all say the same thing-- "that's the guy." narrator: is there a new suspect in this old case? and can an amateur sleuth, a forensic pathologist a handwriting expert a veteran archivist and a master carpenter help john douglas finally solve the crime of the century? douglas: we owe it to the victims' families to know that the person who perpetrated this crime didn't get away with it. narrator: next on nova "who killed lindbergh's baby?" major funding for nova is provided by the following: supporting nova and promoting public understanding of science. and by the corporation for public broadcasting. and by contributions to your pbs station from: additional funding from: inspiring tomorrow's engineers and technologists. narrator: 80 years ago, this narrow country lane led to the scene of one of the most perplexing crimes in american history. and this man wants to solve that crime once and for all. he's john douglas-- legendary fbi profiler who pioneered the use of behavioral analysis for tracking down serial killers and other dangerous criminals. today he has come to this isolated estate in hopewell, new jersey, to try and unravel a mystery as cold as the grave-- the daring kidnapping and tragic death of charles lindbergh, jr., aged 20 months when he was stolen in 1932. wow, that's amazing. after 80 years it still looks the same. narrator: douglas has worked thousands of cases and helped in the prosecution of violent offenders all over the world. but this notorious crime still haunts him. douglas: i have been fascinated by this case for years. there are just too many unanswered questions about who did it and how it was pulled off. what we do know for sure is that the baby was put to sleep up there in that bedroom and the rest of the household was awake when he was abducted. narrator: the crime would touch a fear lurking in the heart of every parent-- that somehow without warning or reason, their child would be taken from them, never to return. douglas: and when you can't solve a crime like that, or come up with satisfactory answers, the case won't go away. because with children, it's like we somehow failed to protect them. narrator: never before had a child this celebrated and adored been so shockingly victimized. douglas: for the first time we all realized that any one of us at any given time can be the victim of a violent crime, because that's exactly what happened here to the most famous family in the world. narrator: with his triumphal solo flight across the atlantic in 1927, charles augustus lindbergh instantly became a global icon. fass: charles lindbergh was the hero of the world, not just of the united states. he seemed to personify the best of an american. young, informal. very handsome, tall, blue-eyed and a bit shy. he's irresistible to the world at that moment. narrator: as this 1927 hit song clearly demonstrates. singer: ♪ lindbergh oh, what a flying soul was he ♪ ♪ lindbergh his name will live in history ♪ ♪ over the ocean he flew all alone... ♪ narrator: when lucky lindy met heiress anne morrow, he not only taught her how to fly, he married her. and when the celebrity couple had their first child, a boy they called charlie, their charmed lives seemed complete. singer: ♪ ...lucky lindbergh, the eagle of the usa. ♪ narrator: but their joy lasts less than two years. newsreel announcer: message that shocked the world comes in on the police teletype. fass: when the lindbergh baby is reported missing, this country is in a state of shock. there's a sense of disbelief that this extraordinary royal prince, really would have been stolen. man: the crime was committed by means of a ladder placed against the house. narrator: with no eyewitnesses and few clues other than a homemade ladder left by the kidnappers the police had a difficult time reconstructing the events of the crime. what emerged as facts were these. sometime between 8:00 and 10:00 p.m. on tuesday, march 1, 1932 one or more individuals came to the house with a homemade folding ladder that left scrape marks on the wall to the right of the baby's bedroom window. the kidnappers apparently climbed the ladder and entered the room through the unlocked window. once inside, they snatched the sleeping baby from his crib. they may have silenced him or rendered him unconscious, because no one in the household reported hearing charlie cry out or struggle as he was taken from his bedroom and whisked away. the kidnappers left the ladder by a service road and used a car to make their getaway. they had placed a ransom note on the baby's windowsill demanding $50,000 for his safe return, and warned lindbergh there would be trouble if he involved the police. the criminals left no fingerprints or other helpful forensic evidence to guide the investigation. so where to begin? as an investigator, one of the first questions i would ask is did they have inside help? this is the first time the lindberghs were here on a tuesday. the house was not quite finished, so the family only came on weekends. they spent weekdays at anne's family estate in englewood, new jersey. but charlie had a cold, and anne didn't want him to travel. so how did the kidnappers even know they'd be here that night? narrator: john douglas wants to profile the type of offenders who could have committed this crime. were they organized professionals or lucky amateurs? one way to answer this question would be to figure out what they intended to do with charlie. douglas: it takes too much planning and resources to care for a toddler. it's a whole lot easier to pretend the child is alive collect the ransom and be on your way. and i believe that's what happened here. narrator: at a late night meeting in a bronx cemetery, the kidnappers did collect the ransom and did get away scot-free. dr. john condon, lindbergh's emissary handed over the $50,000 in a wooden box in exchange for a note telling lindbergh where he could find his baby. but it was all a ruse. two weeks later, a truck driver walking in the woods stumbled upon charlie's decomposing body not five miles from his hopewell home. and from the state of the corpse, it appeared he died the very night of the kidnapping. an entire nation mourned charlie's death as if this child was their very own. fass: there is a loss of innocence that takes place as a result of this case. the kidnapping, the death, all of it makes americans confront the fact that they have witnessed something truly awful here. narrator: the baby had a fractured skull. and when police found cracks in the ladder, they theorized the breaking ladder startled the kidnapper, who dropped the baby by accident. but john douglas disagrees with this scenario. and so does this man. he's former north carolina chief medical examiner john butts, an expert on suspicious child deaths. john butts: it has been proposed that the injuries this child suffered were the result of some type of accident. this is problematic for me because while it might explain some of the injuries, it doesn't explain all of them. on the left side of the child's head there was a fracture line extending from the anterior fontanel the soft spot in the front top of the head to back behind the ear. now, on the right side of the head he described a rounded approximately half-inch in diameter defect behind the right ear. to me, this second injury, the one on the right side of the head, is the one that's most intriguing. narrator: police reports stated that an officer trying to extricate the baby's remains accidentally poked a hole in his skull with a stick and this created the round impact-like injury on the right side. but again, butts is skeptical. butts: in my opinion, an individual pushing or prodding a body with a stick could not poke a hole through the skull under virtually any circumstance. narrator: so what caused this injury? and how did the baby suffer severe damage to both sides of the skull? butts sees one possible scenario. and it's not accidental. it's murder. if he were lying on his left side head down on a hard surface, and he was then struck a forceful blow on the right side of the head by a hammer or pipe, that would compress the head and it might do so with sufficient force that there might be resulting fracture on the left side as well. narrator: butts's theory supports douglas's contention that the kidnappers killed charlie intentionally. and this helps him build a profile of the type of offenders who could have perpetrated this crime. douglas: what i'm seeing here are ruthless individuals with a violent criminal history. they're not first-timers. they are daring enough to kidnap the lindbergh baby and risk the death penalty if they're apprehended. these are hardcore guys. narrator: it took the police two and half years to finally corral a suspect through a combination of foresight and luck. when authorities prepared the original ransom money, they handed out lists of the serial numbers to banks and stores. they also used gold certificates, a currency that would soon go out of circulation, the idea being that the serial numbers on these old bills would be easier for merchants and bank tellers to spot. about two and a half years after the kidnapping a guy pulls into a gas station up in new york and buys about 98 cents worth of gas and pays with a ten-dollar gold certificate. now, the gas station attendant is suspicious, but he's not thinking, "oh this is lindbergh ransom money." he's thinking, "we're off the gold standard now "for about a year or so. the bank might not take this money." so just in case, he writes down the license number of the car on the edge of the bill. and that license number was richard hauptmann's. narrator: when police went to the home of bruno richard hauptmann a german immigrant carpenter living in the bronx, they found $14,000 of the ransom money, a small handgun, and other suspicious evidence. they arrested him on the spot. newsreel announcer: thousands storm the venerable court at flemington, new jersey. narrator: the biggest trial ever seen in america began in flemington, new jersey, on jan 3, 1935. thousands of reporters and onlookers descended on the small town, all scrambling for a front row seat. it was such a mob scene... fass: a lot of people were beginning to express doubts about whether justice could be served in the context of this kind of circus. narrator: at the trial hauptmann presented himself as an innocent working man who would never commit such a crime. absolutely not. are you the "cemetery john" that was in the other cemetery? narrator: but a closer look at his background calls this assertion into question. prior to coming to the united states he had a criminal record back in germany. narrator: mark falzini is the archivist for the new jersey state police museum. the museum's trove of case-related documents includes a detailed history of hauptmann's background in his hometown of kamenz, where he was arrested for several crimes. falzini: he did use a ladder to climb into the second-story window of the mayor's house and stole some money and watches. and one other time he worked with an accomplice where they held up two women that were pushing a baby carriage at gunpoint. narrator: to get to the united states, hauptmann had to escape from jail, stow away on a steamship and lie his way through american immigration. so despite his engaging, clean-cut demeanor hauptmann was bold, ruthless and criminally sophisticated-- the very attributes of john douglas's profile of the lindbergh kidnappers. not to mention his history of using ladders to commit crimes. prosecutors claimed he personally built the kidnap ladder. but hauptmann denied ever seeing it. this is the actual kidnap ladder hauptmann supposedly made in his garage. kevin klein: this ladder is actually kind of tricky to make. narrator: kevin klein, a master carpenter and amateur sleuth has studied every inch of it. i think hauptmann probably found whatever he could and scrounged it up to build this. narrator: the ladder was cleverly designed with three sections that nestled together, making it easier to carry, set up and remove. after the kidnapping, the police brought the ladder to arthur koehler, a wood expert, to see if he could find clues that would lead to the kidnappers. koehler numbered each piece of wood and traced its origin. probably the most important part of this ladder, or at least in terms of convicting richard hauptmann, is rail 16, which is found on the third section here. this rail was positively id'd as connecting to a floorboard in hauptmann's attic. narrator: rail 16 is made of yellow pine. when police noticed that hauptmann's attic contained yellow pine floorboards, they asked koehler to compare a sawed-off board with rail 16. he looked at the grain patterns and drew the conclusion that the two had been connected. there was a small portion missing, but you could draw the grain figure and it matched perfectly. narrator: to john douglas, the wood evidence is conclusive. douglas: if i was working this case and the police found a piece of that ladder matches wood found at that residence i would tell the police, "why am i here? "why did you bring me into the case? you got your man." narrator: douglas has come to the actual flemington courtroom where hauptmann's trial took place. it took six weeks of grueling testimony, but on february 13, 1935, the jury handed down its verdict. (gavel bangs) guilty as charged, with a sentence of death. but was hauptmann the only person involved in the crime? as he waited in his cell prosecutors, convinced he did not act alone offered him a deal: they would spare his life if he named his accomplices. yet he never wavered from his claim of innocence, and thereby sealed his fate: execution in the electric chair. because he chose to die when he could have saved his life many people began to wonder if bruno richard hauptmann might have been innocent after all. at the new jersey state police museum in trenton john douglas studies artifacts from the case and reflects on hauptmann's claim of innocence. douglas: i've seen a lot of cases where a criminal swore he was innocent, went to his death, and we later found out through dna or other evidence that he was guilty. some criminals just want to try and protect the family name. hauptmann had a young son, and i think that's why he claimed he was innocent. narrator: anna hauptmann maintained her husband's innocence to her death in 1994. and a recent german television documentary set in his hometown has again raised questions about his guilt. (speaking german) narrator: so controversy about hauptmann's conviction lingers on. douglas: but we're left with only three possibilities: one, that hauptmann is innocent. two, that hauptmann is guilty and acted alone. and three, hauptmann is guilty and had others to help him. narrator: douglas is convinced hauptmann is guilty. and he's equally certain he had accomplices. one reason is the ransom money. douglas: what's unusual about the ransom money is that one third of the money is in hauptmann's possession. where are the other two thirds? did they go to two other people? narrator: the other reason is douglas's experience as a psychological profiler. douglas: i've seen many, many cases like this in my career and usually what you need is multiple offenders who can reinforce one another psychologically and feed off each other to perpetrate a crime like this. the night of the kidnapping it was dreary, it was dark it was muddy. it was way too risky unless i have criminals around me to hold the ladder do the surveillance, give me the high sign. it's not going to be one person perpetrating a crime like that. so is it two people, three people? for sure it is not one person. narrator: but no suspects other than hauptmann have ever been found, and douglas wants to know why. so he asks mark falzini, who knows the historical record better than anyone. you know, mark as an investigator the first thing that really kind of strikes me and kind of stands out is that once hauptmann was arrested, the investigation kind of shut down. you know, why? why was that? it had been a two-and-a-half year investigation at this point, and they were under a lot of pressure to put an end to it. remember, lindbergh was the world's most famous man at this time, and they had to end this thing. so they just wanted everyone off their backs, i guess. exactly, yes. the police must have interviewed thousands of suspects here. you have thousands upon thousands of files. the police did interview quite a few people. they interviewed people at lindbergh's house. they interviewed the staff at the morrow estate and all of hauptmann's friends and associates. any good leads? there were a few leads but they all end up going nowhere. i want to throw a name at you: john knoll. does that ring a bell? did that name ever come up in the investigation? no. his name does not appear anywhere in the collection. narrator: so who is john knoll? and why is john douglas looking for him? douglas's interest in knoll comes from this man-- bob zorn. zorn's quest to link john knoll to the crime goes back to his father, gene zorn who as an adult read an article on the kidnapping that triggered a memory of a dramatic childhood incident-- a memory that put father and son on the trail of a lost kidnapper. this whole story begins in the summer of 1931, when my dad was a 15-year-old boy growing up in a german neighborhood in the south bronx. and my father had a neighbor who lived three doors down from him, a german immigrant and a deli clerk named john knoll who encouraged my dad to take up stamp collecting. and one day in the summer of 1931, john invited my dad to go to palisades amusement park in new jersey where they had the world's largest saltwater swimming pool. and there waiting for john were his younger brother walter, another deli clerk whom my father knew, and then a third german-speaking man. well, my dad heard that these two men john and walter, were calling this third man bruno. and the three men were talking about some place called englewood. narrator: englewood, new jersey, was the location of anne morrow lindbergh's family estate. the lindberghs stayed there while their hopewell home was under construction. fast forward to december of 1963. by this point my father is a 47-year-old bank economist living in dallas. and he walks into his dallas barbershop, and he reaches for a magazine called true. december 1963 issue. and in it is an article about the lindbergh kidnapping. and certain words just seem to jump off the page. of course there's bruno. bruno hauptmann. my dad had remembered that john and walter knoll called this third man bruno. and then there's englewood where the lindberghs had been living in 1931. the author of the article stated that hauptmann was undoubtedly guilty, but that he had worked with accomplices who could still be at large. and one of these accomplices was a man calling himself john. narrator: "john" is the name of the kidnapper who was given the ransom at the bronx cemetery. and gene zorn began to wonder if this "john" could be john knoll, the deli clerk from the bronx. after his father's death bob zorn took up his dad's quest to link john knoll with the kidnapping and made several discoveries. but he wanted an expert familiar with the case to validate his findings. that's when he contacted john douglas to hear him out. the men went to woodlawn cemetery in the bronx where two critical players make their début in the case. the first was dr. john condon, a retired bronx schoolteacher. condon idolized lindbergh and placed an ad in a bronx newspaper volunteering to mediate negotiation between his hero and the kidnappers. inexplicably, both parties accepted him. one of the most infuriating things about the lindbergh case is that dr. condon is the key to the investigation. he was the one who met with one of the gang members in the cemetery twice. he was the one who turned over the ransom money. he was the one receiving all of the ransom notes. dr. condon was also a blowhard. he liked to embellish things. i am more than pleased to solve that mystery on which i have been working without cessation. when you read his statements you don't know what to believe. you know, you never know what to believe with dr. condon. narrator: in condon's account of his first meeting with the kidnappers, he goes to the cemetery, but at first can't find anyone. zorn: and then after a while a man who had secreted himself inside the cemetery reached out and started waving a handkerchief to attract condon's attention. douglas: is that one of the kidnappers? zorn: yes, it was one of the kidnappers. douglas: did he say anything? well, he had a heavy german accent. and the first thing he said was, "have you got it, the money?" narrator: the man with the german accent says to call him john, and becomes known as cemetery john. condon is the only person ever to see cemetery john, so his description is critical to bob zorn's quest to match him with john knoll. he said that he was a guy built about like me-- i'm 5'7", 165-- with a high forehead large ears, a pointy chin, and then a large lump or fleshy mass at the base of his left thumb. what do you mean? well, it would appear to be an abnormality. a photograph i have of john knoll clearly shows that there was something very abnormal about his left thumb. narrator: this photograph, taken a few years after the kidnapping is the best view we have of both of knoll's thumbs. hand specialists are divided on whether they reveal a clear abnormality. but both thumbs are large and discolored so he might have had some physical anomaly. and did the police... at any point did they do a police sketch based on the description provided to them? they did. tell me about that. well, the police took the description and they had a sketch artist do a sketch of him. i got a photograph of john and then i set that photograph next to this police sketch and it was a dead ringer. and i've shown this to hundreds of people