thank you for joining us. i'm joie chen. our criminal justice system depends on czechs and balances, prosecution and offense, punish the guilty and protect the innocent. what happens when someone puts a thumb on the scale of justice our first story looks at witness identification. it may surprise you it's the cause of as many as three out of four wrongful convictions. our investigation found that juries almost always convict if there's an eye witness, even when there's proof the suspect couldn't have done the crime. . >> when the verdict came back and it was guilt on an outline counts. the courtroom erupted in applause. give him the gas. i heard them sniggering and lawyering. everyone thought they had the right men. police department. prosecutor's office, most of the people thought they had the man. >> reporter: before prison changed everything. kurt's story was a simple one, race said on the maryland eastern shore, fishing and crabbing like his father and his father's father before him. bloodsworth left to join the marines. he was honorably discharge said. he was never in trouble with the law until the early hours of august 9th. bloodworth was 22 years old, and house. >> 2:40. i remember looking at the clock. i walked through the door. pistol's drawn. stepped outside. you son of a bitch, someone said. >> nine-year-old dawn was raped and murdered. two weeks earlier. her body found near the bond in a wooded area. >> stuck my head in a police car. that was the last time i've seen it. eight days. >> that's the time. >> yes, two years on death row for something i didn't do. >> baltimore county police put out a sketch of the suspect, based on a description given by two little boys. we saw the walk in the woods. using an identikit. they helped the children describe the face. >> it sounds to me like mr potato head. it's a random buffer of eyes ears, noses and faces. they start out. the eyebrows, and a nose. >> using the crude tools of the identikit. image. >> the moustache, what did it look like. they said it was a full-man tune. the police added it -- never added it to the composite. >> a woman that lived saw the drawing on tv. and called the cops. she called in saying it looked like me. >> the picture was plastered all over the news. played in an endless loop. by the time witnesses saw him. anyone that saw tv news, knew what kurt bloodsworth looked like. everyone in court said they watched me on television the entire weekend. for four hours in the line up. >> do you remember the line-up? >> we do, two little boys didn't identify me, two weeks later they called the police and said "look, it's really number six." that's the position i stood in. >> there were three other witnesses who picked mim out. -- him out. >> the witnesses were half-heart and mistaken. i never tried to say that anyone was lying, they made a mistake. >> you were picked out. >> a photo array i was picked out of. >> photo array. these witnesses believed. >> i think they believed with a little help. there. >> not a shrid of physical evidence linked bloodsworth to the crime. five defense witnesses testified he couldn't be there. but the testimonidentified bloodsworth as the man that took little dawn hamill son into -- hamilton into the woods was enough to convict him. he spent nine years in prison, two on death roup. >> from the time i was arrested to the moment i was released i told everyone and anyone i was an innocent man. i signed my correspondence that way. respectfully submitted kurt nobel bloodsworth a. i. m. an innocent man. >> he became a prolife ig reader and came across a story about a approach. science saved you. >> in the end it was d.n.a. >> reporter: bloodsworth was the first person in the united states exonerated by d.n.a. testing. which found that kurt didn't kill dawn hamilton. it was sitting in the cell. it was end of april. >> a guard stuck a poist-it note. i'll never forget it. >> it's urgent. call your attorney. and they go kurt, you're innocent, man, you're innocent. >> i know that. when are you going to get me out of here? >> the d.n.a. evidence proved not only that bloodsworth didn't do it, but another prisoner was the real killer. kimberley resembled the original description. kurd bloodsworth case was one the city and county police declined to talk about. his name is a reminder to other police prosecutors about what can go wrong. >> there's no police officers, prosecutors and judge that wants to punish the person. the internal affairs unit of department. >> how good are people as witnesses. not as good as we think. changing the investigation, beginning with a procedure that started kurt bloodsworth down the road. the county p.d. became one of the first in the country to do away with a 6-pack photoarray. the kind used. >> in favour of a sequential photo line up. in which the suspect was one at a time. >> give it to him as six individual photos, and we ask them to flip through them, make it look at all of them. make is decision about each one as they go through the time. >> reporter: homicide detective said it helps to pick the right suspect. not one that looks right. the officers can unintentionally influence a witness. >> if they are honest and scrupulous, they know the right answers. they may gave off an unconscious queue. they may bet excited. don't. >> reporter: he implemented a double blind process where neither the detective or the witness nose if there is a suspect in the photoarray. >> if you give that photo array. you have no idea what the right answer is. the study shows you'll get a true result. >> do you believe what happened today? >> no. i don't believe it. depends on the jurisdiction. you can sign a person to death row in the united states, by circumstantial evidence. kurd bloodsworth doesn't get back to the water often any more. instead he's an activist. >> witness identification was one the reasons that lawful convictions have in the states. >> he wants forms like pg country to be widespread. >> i say to people if arrested, don't say anything, shut your mouth, hide your face. you see that on tv. there's a reason they do that. >> why? >> because somebody could misidentify them, and it's happened so many times. we are not nipping it. we are not infallible. we make mistakes. if this could happen to me, my intellect tells me it could happen to everybody. >> when we return, police get a false confession from an innocent person. >> i cannot denying it -- kept denying it. why would anyone confess to a crime they didn't commit. it may see change, but there's grows evidence it's not a rare thing. in new york states our next story takes place, half of all places of wrongful qugzs involve a -- convictions involve a false confession. half. sara hoy has the story of a man did not commit. >> reporter: sham own was roller skating with two friends when see was killed. >> two detectives came. i was sleeping. my sister opened the door for them. they came back in the department. that morning, he was dragged out of his brooklyn apart: it was home. >> 18 years old at the time. i don't know why he's there, why they take me there. i have no crew. it happened to abruptly, no one questioned where i was going. >> reporter: we travelled with moses to the scene of the crime, a public housing complex in the midst of being demolished. what is going through your mind? >> an out of body experience. they say i was here and accused me of doing something. >> reporter: place accused him of shooting a political girl. >> they take me to the precinct. when i arrived there, they sat me at cubicles, with a detective, and he explains why i'm there. relieved. >> relieve. >> relieved in the sense that i know that i had nothing to do, and i knew what they were questioning me for. moses thought they had be back for his family. it was the beginning of a 12 hour investigation. >> i kept denying it. they began to get aggressive. after i denied it for several hours, they got tired. this is when detective came into the room. and he began to physically assault me. >> what does that mean. >> nining that he physically used his hands. slapped me, choked me and the rest of the officers helped me. so i went and protected myself, i wouldn't lash back out at him. >> reporter: detective lewis garcella was legendary, known for making arrests and getting convictions. in 1995, the year moses was charged with murder, the violent crime rate took a nose dive, contributed to new aggressive policing. the murder of 4-year-old shimon outraged the community, and suspect. >> at that point my mind went into the survival mode. danger. >> yes, i did, because at that point they weren't acting like detectives. gang. >> and i'm saying that they wouldn't sent anything outside of a confession, and now that i'm realising that, so that, with not knowing the law, of course, i say, well, i tell them what they want to hear. i can prove that that was a lie. >> reporter: detectives wrote up a confession. to put an end to the nightmare, moses signed it. i have to ask a question. why in the world would you do? convicted. i just - the only thing that i prayed for was that the right people to hear it. >> but the confession with his signature proved to be more influential than any other piece of evidence in court. >> who ever heard of false confession, someone would confess to a crime they didn't commit. that's what they believe. >> reporter: this is a president of a public relations firm. after playing a role in a number confessions. >> 50% of exonerationing involved a false confession. >> 50%. 25% nationwide involved a false confession. it is very common, and police are encouraged to get confessions. it's the middle east compelling piece of evidence for a jury and results in a conviction. once it's in the prosecutor's hands, and before a judge, and before a jury, it's over he received stacks of letters from inmates looking for help. what about the guys in prison. the letters. i'm 33 years old, i've been incarcerated for 15 years, and maintained my confession was a false one. >> shaun harris wrote a letter saying please help me. 33 years old. that is who is in prison. these are full of legal cases, information about the families, cases, and innocence. that's what they are sending us, me, every day. >> recorded. >> in sunday moses's case we needed to see the police officer. we needed to see when he choked confession. that's what we need to see. a jury needs to see that. anything less should not be allowed in court. less than half of all states requires interrogations to be recorded. after seeing the confession, a jury convicted him of second degree murder, sentencing him to 16 years to life. >> i was shocked. there was other people - i couldn't say - i couldn't say much. i'm a very strong-willed person. but for a second, just for a second, suicide flashed through my mind. moez's mother was beside herself at the thought of her youngest of eight children spending his life in children. >> i went through it, a lot of the surgery, i went through depression. the pressure was so bad, i wanted to go in the train track, that's how bad it was. >> moses began to serve his sentence. in 2013, lewis became the target of an investigation himself. accused of lying, cheating, and other misconduct. actions have tarnished 50 cases which the attorney is reviewing. moses was one of them. no physical evidence whatsoever. no blooded, fibres, hair, ballistics. bullet strayses, powder revenue burns, not a shred of physical evidence to connect him with the crime. we began to investigate the case. the first thing we did is talk to both of those eyewitnesss. and these are people that had no reason to lie at the time, and no reason to lie now. one of them, the cousin of a little girl was the close friend of a mother of a little girl that was killed, and they told us that sonny person. >> reporter: in light of the new evidence and the da's review, moses went before the parole board to proclaim his innocence. the new york board of parole released him. >> welcome home, man. >> reporter: days before his 38th birthday, sunday mozs made his way home, into the arms of those that did not stop believing in his existence. >> it felt like a dream. so much is running through my head, i'm getting my freedom. that freedom is basic to life. these are strong young men. we are here getting life back. will he be the same again? i pray for a long life. i pray that i'm alive to see this happen. i know god will keep me next, evidence tampering, one woman, a chemist working for a state crime lab tainted potentially 40,000 cases. when reasonable doubt returns. camden new jersey has held the title of america's most dangerous city. crime rates have dropped by 25%. "america tonight"s adam may goes to find out how they did it. >> reporter: a camden police officer confronted by a woman, hiding in a shower with a 12-inch knife. for police, the dangers of the job are very reel. but nothing like it used to be. >> shootings, homicides up here. there was a homicide, a shooting in a store behind us. >> reporter: there's a lot of crime in this area. >> absolutely. >> reporter: it's hard to imagine, because it looks very clean. >> tremendously different. >> reporter: officer christian jeffreys walks the beat in camden's fair few neighbourhood. one ever 400 officers now on patrol. their orders engage in real community policing. more boots on the ground. eight hour patrol shifts on foot. making arrests like this one more common. >> reporter: the city is introduced a state of the art surveillance system, more than 100 live-streaming cameras monitored 24 hours a day. >> we have mobile beach, and these officers are doing something similar, but through a camera. >> reporter: the new assistant police chief says the cameras are not only helping solve crimes, but police rl using them to pre-- are using them to predict crimes, the broken window theory of policing. >> we look for those things indicative of crime. when we see people conduct themselves in a way, rather than waiting for a fight to break out. we want to be in front of it. whether it's urinating in public, other things creating a public safety nuisance. it. if you attack the little things, it impacts the bigger things, and we believe that. if we were to use the cameras for the needle in a haystack, where we wait for the one shooting alone. the impact would be minimal. >> so what we want to do is be out in proof it. they are indicative of crime. >> the country place are taking the network of cameras to a new level, launching what they call a virtual neighbourhood watch. allowing residence to tap into the cameras, a first of its kind programme in the nation. >> brian morten coaches little league at a park in north camden, a haven for prostitution and drugs. now, four surveillance cameras watch children at play. >> playing baseball and taking the first swing on a swing. what can by more natural. we attribute that to new surveillance. >> a few hundred residents have been given access to the interactive community alert network. tips or anonymous, and users are empowered to move the cameras and zoom in. >> they will never know the neighbourhood as as well as the residents. they know the historic am relationships, the things that are going on in the neighbourhood when we are not there. they are able to put it in perspective for us, and help them police the neighbourhood. >> the police call the strategy community policing. >> community terrorising. it's pushing the community, creating a hostile environment. >> this is an activist in camden, and has lost trust in a local police force, and says officers are under a lot of pressure to perform, so the tactics are often heavy-handed. >> there's a lot of complaints against the police officers and attackers, and how they are harassed at young people. we have lawyers looking for people that have been stopped and frisked illegally and stopped like that. changing and pushing that back. they stop young people that don't have a record and harass them and put them into trumped up staff. we have this and that on that. it's a negative. >> reporter: one thing everyone agrees on, camden's crime problem is not just about law enforcement. jobs are scarce. generations deep. >> reporter: there are signs of change. police interacting with people, working together to make the city safer. >> reporter: that is a hope shared by many in camden. as we have seen, many of the pillars of our criminal justice system are subject to reasonable doubt and can no longer be taken for granted. justice hangs in the balance. >> a fourteen-year-old... murdered. >> whistling at a white woman... in mississippi? >> america tonight opens the case... >> never thought that he would be killed for that. >> that started the push for racial justice. >> that was the first step in the modern civil rights movement. >> could new evidence uncover the truth about that gruesome night? >> i wanted people to hear the true story of till. >> north korea's leader orders his troops to be ready for war as tensions with the south escalate. from al jazeera in doha, also ahead, the greek prime minister quits and calls snap elections. how it's just the latest in a series of shrewd moves. low on staff and supplies. we are in iraq where the country's healthcare system is struggling to survive. and surrounded by sewage, why these people in south africa are forced