murder? >> the question is who is going to benefit by the two deaths? >> jessica was the only child. >> or was there someone else that stood to gain? investigators would discover a clue. >> someone with a sick mind. that is all i know. >> welcome to dateline. it was a hobby that turned into a passion, collecting. they were good at it. amassing a fortune they kept in their home and also where their bodies were found. the question was obvious. who stood to gain with the answer to who killed them be that simple. here is dennis murphy with the collector. >> if your travels take you to the ozarks, you had trout or bass fishing on the mind or perhaps head to branson. there was no tour guide that would have directed you here in missouri. that is a shame. an old curiosity shop well worth seeing. floor to ceiling collectibles, valuable stuff everywhere the islanded. >> anything from coins to arrowheads. ten to 15,000 books. >> did these collectors have a less discerning eye when it came to sizing up people? did it go towards explaining the dreadful toll in the house that evening. >> i said he is off in some way. he could be a psychopath. it scares me. >> april 30th, 2014 did they fall prey to someone they believe could be trusted? >> iad to be lowered to the ground. i started crying and screaming. >> such good people. why. why. >> springfield, missouri, the queen of the ozarks. gary terrell grew up poor and knew his adult life would be all about education, teaching kids in the classrooms by day. the history book in his lap at night. he and his wife raised a girl and a boy who sadly died young of brain cancer. they lived and gardened in the same house for 25 years and designed it themselves. life in mizner park was good for the two. jessica remembers how close they were. >> if my mom went shopping my dad took her, the garden together, talking on the phone several times a day. personalities, gary was the fun, outgoing one. >> once she warmed up to you she was alive. >> when gary retired he suddenly had all of the time in the world to visit civil war battlefields, scour flea markets. >> he was big in to buying and will selling gold and silver. he constantly collected coins and bought gold and silver trinkets. gold and silver went into one of five saves in the house but the coins and artifacts, out on display. what was the most unusual piece? >> the walrus trus tusks. >> they were rare and each worth around $10,000. >> how would he find these things? >> i am not sure. they did go to flea markets and garage sales. any time i would ask him where did you get this. in my travels. >> in 2013 jason murray became one of the family when he and jessica got engaged. he remembers the walrus tusks and other unusual items. he had so much stuff. >> jessica and jason lived 300 miles away in oklahoma city. jessica spoke or texted her parents several times a day. that all changed on may 1st. >> i had called my mom on the way to work like i always do. i thought maybe she is in the bathroom or outside. called back and still didn't reach her. >> jessica called the springfield police and asked them to go by the house. all of the doors were secure. no signs of forced entry or that anything appeared to be out of place. >> the officer had no cause to force the way into the house and left. jessica said that she was worried. she and jason jumped in the car to make the five-hour drive around 7:00p.m. >> as we were coming around the corner to the house, i hit the garage door button. both of the cars were in the garage. >> that was bad news for you. >> yes. >> what did that imply? >> that there was something terribly wrong. >> jessica called 9-1-1 without ever going past the garage into the house. two officers arrived within minutes. >> they entered the home. another officer arrived. another. another. >> nobody said a word to jessica and jason. they noticed police blocking off the area with crime scene tape. >> i grabbed on to the officer saying what is going on. why are they calling for crime scene tape. he i don't know what is going on. i just know there are two people in the house that are deceased. >> chilling words but nothing compared to what investigators would find inside. >> seems to be an element of personal anger. close quarter killing with a weapon in their hand. >> definitely seemed to be personal with the brutality involved. y seemed to be personal with the brutality involved how did olay top expensive creams? like this with hydration that beats the $100 cream in every jar of regenerist retinol24 collagen peptide new vitamin c and the iconic red jar can't top this skin shop now at olay.com let's get ready for jalapeñoooo popperrrrs! can you hand me some potato skins. theyyyy're loooaded! turns out, michael buffer speaks like that all the time. and it turns out the general is a quality insurance company that's been saving people money for nearly 60 years. and in this corner, coconuuuut shriiiiiimp! for a great low rate, and nearly 60 years of quality coverage - make the right call - and go with the general. let's get rrready for garlic breeeaaad! >> as darkness closed in on springfield, missouri, the daughter that asked local police to check on her parents was being told two bodies were found inside her parents home. they didn't identify them but jessica said she knew it could only be her mom and dad. >> and i started crying and screaming. because i knew. it was my worst fear. >> her fiance, jason, was by her side trying to console her. >> she was beyond upset kept saying i am sorry mom. officers quickly grasped the cold stomach churning truths. the deaths were not accidental. the detective was one of the first on the scene. we could see there was a deceased male. >> his pants were pulled down. what did you make of that? >> we didn't know. the only thing we could think of is that he is trying to get away from someone. they are grabbing ahold of him. >> or was he rifling his pockets for a key or combination. in the office downstairs, the detectives found. >> she was lying on the ground face down. >> was this a violent home invasion? jan and gary had more than a half million dollars of valuables in the house for the grabbing. a botcher robbery was a likely scenario. it appeared somebody tried to pry the locks open. >> they didn't get inside? >> it did not appear they did, no. >> that would suggest somebody is looking for something. >> yes. >> if robbery was the plan the killer left the museum intact and nothing appeared tossed or out of place and the nature of the killings. gary was shot as well as beaten spoke volumes to the prosecutor assigned to the case. >> it seems to be a element of personal anger. close quarter killing of someone with a weapon in your hand. >> yes. it definitely seemed to be personal type of killing. >> investigators determined jan and gary were likely killed the night before. search as they could for the murder weapons, officers came up empty handed. they did recover unusual evidence. >> around jan's body there were small white flakes of a substance that were obviously from the murder weapon or on the murderer's body. there were similar flakes found by the wound to gary's head. >> bagged them and sent them off for testing and recovered something else that could be a crucial piece of evidence. a discarded laytex glove. >>tex glove. >> totally out of play. there is no way gary or jan would have left the glove there. >> did it belong to the victims or the killer? no one knew. >> it is collected. you don't know what it means. >> don't know what it means. collected and sent to the highway patrol crime lab. >> no idea or a working theory of why the couple was murdered but had a sequence of what made sense as to the order of death. >> hard to believe gary had shot upstairs if jan was fully functioning and mobile. >> that tells you she is the first victim? >> most likely he arrives while it is on going or the killer is waiting there for him. but yes. >> how did the killer gain entry to the house? >> there were no signs of forced entry. >> the doors are all intact. how did the killer get in? >> only two ways. one would be to have their own access device. or let into the house. >> it did not appear to it be a random home invasion but the killer or killers were someone the couple knew. was it a person gary encountered in his antiquing travels or was the perpetrator much closer to home. >> i was shocked. confused and baffled. >> who had a motive? investigators have at least one idea. coming up. >> she was the person to benefit from the crime in terms of getting money. >> the only child from parents well-to-do. a lot that would be left to her. >> when dateline continues. e le. >> when dateline continues >> two dead. the wife beaten about the head downstairs, husband shot twice upstairs. springfield police determined this was no random breakin gone wrong. jan and gary terrell's modest home was filled with valuable items and at first glance nothing was taken. an early supposition was someone close to them and the closest person was daughter jessica. >> she had the most to gain. >> that night detectives asked jessica and jason down to the station to answer a few questions. cops did not let on they were talking to them as grieving relatives and also suspects. the interviewer withheld details about the crime scene. he even threw out a theory that wasn't true, murder suicide. jessica seemed to go with it. my dad has been super depressed and made comments. i said if he said something stupid call the police. police had another reason to be suspicious of the daughter. you know they don't want to see, you know, the bodies in there and call somebody else. >> detectives pressed the couple about the movements that day. what they did or did not do at the scene. had they tampered with the tornado shelter in the garage. >> did you think if we are looking at a situation where we have to call a lawyer and be careful about what we say? >> i did a little bit. >> neither jessica or jason asked for a lawyer and asked for more detail about what was in the tornado shelter that had been tampered with. >> for investigators the interview was a test. >> how are you going to hold up. are you going to give answers we can verify or -- >> you intended to sweat them. >> that was the detectives intent to the degree of making sure we get the truth. >> had they passed? detectives let them go but held on to jessica's car. >> why did they have a reason to look in your car. >> i didn't know. >> jessica had to call family and friends to tell the news about her parents. her uncle larry was at his law office when he got the call. >> i collapsed on the floor. >> you were a mess. >> i was a mess. the unknown was terrifying. >> larry was not shocked or outraged to learn his niece was being looked at as a suspect. he was a criminal defense attorney and former prosecutor. >> i knew she had to be eliminated. i understood that. >> the case did keep moving but after a full week of investigating the daughter and fiance were not eliminated. detectives called them back to the station. this time interviewed separately. cops figured out the murders took place the night before the bodies were discovered. where were he and jessica then? >> we went to the pizza hut. probably 5:30 and went home, five hours away in oklahoma city. right to the point. >> you have any reason to harm gary or jan? >> not at all. next jessica answering questions about her relationship with her parents. >> are they paying any of your bills? >> my at&t bill for my cell phone. pay my car insurance. i think that's it. >> i am going to ask, did you have any ill feelings towards your folks or anything you were mad at them for or any reason to want to harm them or anything like that? >> my parents were my life. >> to better your financial situation or anything like that? >> no. if i needed something all i had to do is call and ask. >> you are a suspect in your parents double homicide? >> yes. it was more just going through there and saying i didn't do it. >> police asked jessica and jason for d.n.a. samples and set out to verify the alibis. >> my boss and i took a trip to oklahoma city and spoke with the fellow employees, jessica's boss. >> coming up, gary's best friend offers detectives some clues, including texts that he said that he saw on gary's phone. did someone need cash badly enough to kill when dateline continues. h badly enough to kill when dateline continues. dio being tuned] welcome to allstate. ♪ [band plays] ♪ a place where everyone lives life well-protected. ♪♪ and even when things go a bit wrong, we've got your back. here, things work the way you wish they would. and better protection costs a whole lot less. you're in good hands with allstate. click or call for a lower auto rate today. here is what is happening, more than 2,400 flights were cancelled on saturday. airlines are experiencing staffing shortages due to the omicron variant. and dan reeves, a former dallas cowboys running back and nfl head coach died saturday at the age of 77. reeves coached for three franchises and was a member of two super bowl-winning teams during his career. now back to dateline. >> welcome back. from the beginning the terrell's daughter and soon to be husband were the main suspects in the brutal murder. but was there someone else that also had a motive? here again is dennis murphy. >> on an early spring saturday in may 2014, the day jessica planned to go wedding dress shopping with her mother she was burying both of her parents. >> i basically just cried. i was constantly ill. >> what she was going through at that point was unfathomable. she is just broken. >> the funeral service held in the mountain grove school district where gary worked for 30 years. nancy was a school board secretary. >> hard to believe something so bad could happen in springfield. somebody that you know. my heart goes out for poor jessica. >> it was a huge comfort to jessica at a time she needed it the most. word got out the cops were looking at her. >> yeah. lots of rumors that i did it. >> it got tiring to hear people say you need to look at the daughter. >> they did take a hard look. >> they did. >> they think the daughter killed him. she is in cahoots with her fiance. my circle was not believing that. >> police and prosecutors came to the same conclusion. jessica and jason were innocent. >> everything they were telling the police, the police were able to corroborate and verify. >> they went through everything. alibi was checked out top to bottom. >> when the d.n.a. results came back on the latex glove, neither was a match. it belonged to an unknown male. >> was that a relief. we knew we didn't do it. when jason went back to jessica's parents house for the first time, he noticed something was missing. >> there was a display of ivory pieces and multiple walrus tusks engraved art type of things. they had been moved. >> walrus tusk. jason told police one of the prized tusks could be the murder weapon. jessica noticed someone was at her dad's desk where he sorted coins. >> he kept them in coffee cans and bags. he would be sorting them or organizing them. >> a container was missing. the killer would have known the real valuable only if he moved in the same antique circles as gary. >> sounds plausible. >> that was a big worry that i had. >> as they dug into gary's business dealings no suspects emerged. few people had any idea how wealthy they really were. >> they did not show that type of wealth to people. always kept quiet. the people that he would interact with were reputable type of people. >> because there was no forced entry to the home larry offered up the limited list of people that had access to the house. officers were reaching out to others. gary's closest friend, mark porter. a former school superintendent. he first came to the district and drove a jaguar. they seemed to get along well. mark went down to the police station to talk with investigators. >> all right mr. porter. it's mark, correct. >> yeah. >> do you mind if i call you mark? >> that's good. >> i want to touch base and talk to you about how you know them. how long you have known them. >> i have known gary for 15 to 20 years my assistant superintendent. i was superintendent. >> mark knew a lot about gary's coin business. >> he has people all over missouri that collect for him. i know he goes to hotels and meets people. he runs ads in the paper. >> gary set up one of the meetings around the time of the death and involved a lot of money. >> he was going to sell $50,000 of gold for cash. it was actually a buyer that was going to give him $50,000 cash. >> he mentioned text messages he saw on gary's phone from another guy. >> gary asked to read some of the text messages. there were five in a row from some guy he taught in a class asking for money. >> remember, gary was shot as well as beaten. could it have been with one of his own guns? >> gary has guns everywhere? he likes his guns. mark gave detectives a detail that took them by surprise. >> he was supposed to meet me 8:00 wednesday and didn't show. >> wednesday, the night of the murders. the first police were hearing of gary having plans that night. what else did the best friend know? >> coming up, mark gives a detailed account. one that troubles investigators. >> there were several things about the story that raised questions. >> when dateline continues. rai questions. >> when dateline continues possi. with rybelsus®. the majority of people taking rybelsus® lowered their blood sugar and reached an a1c of less than 7. rybelsus® isn't for people with type 1 diabetes. don't take rybelsus® if you or your family ever had medullary thyroid cancer or have multiple endocrine neoplasia syndrome type 2, or if allergic to it. stop rybelsus® and get medical help right away if you get a lump or swelling in your neck, severe stomach pain, or an allergic reaction. serious side effects may include pancreatitis. tell your provider about vision problems or changes. taking rybelsus® with a sulfonylurea or insulin increases low blood sugar risk. side effects like nausea, vomiting, and diarrhea may lead to dehydration, which may worsen kidney problems. wake up to the possibility of lower a1c with rybelsus®. you may pay as little as $10 for up to a 3-month prescription. ask your healthcare provider about rybelsus® today. >> springfield police were talking to gary's best friend, mark porter, who suggested plenty of theories about why gary was killed saying gary's money was cat nip for all kinds of folks. mark revealed something detectives didn't know. they had plans to meet at mcdonald's on the night of the murders. >> i waited a probably good -- i got there about 7:45. >> i went to the house. knocked on the door. he will go and say i forgot. my bad. i'm in kansas city. >> mark said gary stood him up before. no big deal. he went back to his office to do work. >> there were several things that raised questions. why would you wait 45 minutes for someone and not pick up your phone and give them a call saying what's up. did you forget. why drive across town if he wasn't concerned about his friend missing dinner. >> he drives across town to knock on the door when his office is across the street. >> inside the interview room the detective decided it was time for a break. >> give me a couple of seconds. can i get you anything? trying to make sense of it all, including this bit of information, gary's brother told police not long ago mark asked gary for a loan and put the request in writing. an eye-popping $250,000. >> that is the kind of money if you get it out of your house a second mortgage. >> did your father consider it for a heart beat? >> no. when he talked to us about it he was kind of laughing. >> strange, not only with mark, gary's former possess had a nice pension as a superintendent, he was earning a six figure salary at ibm. brother larry suggested mark might have a gambling problem. >> i knew he had a bad financial issue. >> the tone of the interview changed completely. >> have you ever asked gary money for yourself? >> no. only for in trade or buying. >> suddenly mark porter was in the hot seat. >> i do not have a large gambling debt. >> no. that is not true. not true. >> he denied asking for the loan saying the only time he discussed large sums of money with gary is about a real estate deal. then detectives asked him the question they asked everyone else. would he offer up a d.n.a. sample. >> a cheek swab i will ask if you can do that. >> i am going to wait. >> any particular reason. >> i don't want to do something my attorney would say you shouldn't have done that. >> why would you not give us a d.n.a. sample. you are telling us you are not sure you will give us a d.n.a. sample. >> police let him go, but the investigation suddenly shifted away from the workers of the terrell home and towards mark porter. some detectives checked out his alibi and others mined other avenues for leads. one cop thought to check a local database of pawnshops to see if the missing items were recently sold. the search led them here to r & k coins. it was just two days after jan and gary was killed when kelling eding ton was working behind his desk and a guy with a tub of coins walked in. are. >> was he okay. normal. >> looked like any average guy to me. nothing actually stood out about him at all. >> he had piles of dimes, quarter, 50 cent pieces. he had $1,210. >> i paid him $18,351. >> $18,351. a lot of money. not far off of the value of the coins jessica reported missing from her parents home. >> when he walked in and stacked the coins and did the transaction, your security cameras caught it all. >> secure did. >> so, who was it? >> coming up. how a mcdonald's coffee cup was about to blow the case wide open. >> does your dash board light up when you hear that? >> i can't describe the emotion of it. >> finally a family learns the truth. >> i remember falling to the floor. >> when dateline continues. the floor. >> when dateline continues brandw way for you to sell your car. whether it's a year old or a few years old. we wanna buy your car. so go to carvana and enter your license plate answer a few questions. and our techno wizardry calculates your car's value and gives you a real offer in seconds. when you're ready, we'll come to you, pay you on the spot and pick up your car, that's it. so ditch the old way of selling your car, and say hello to the new way at carvana. ♪ and i'm gonna keep on lovin' you, ♪ ♪ 'cause it's the only thing i wanna do. ♪ turns out everyone does sound better in the shower. and it turns out the general is a quality insurance company that's been saving people money for nearly 60 years. ♪ 'cause it's the only thing i wanna do ♪ shaq: (singing in background) can't unhear that. for a great low rate, and nearly 60 years of quality coverage - make the right call and go with the general. -hey. -hi. and nearly 60 years of quality coverage whoa, nice car. thanks, yeah. i actually got a great deal on it too, although my interest rate is awful. have you checked your credit? i got like a free score from some app or something like that. but lenders don't even use that score. creditrepair.com has a free credit snapshot that can show you exactly what's happening with your credit score. and killing my interest rates. well, great seats though. -thank you. -like really. just knowing your score won't improve it. instead, work to actually fix your credit with creditrepair.com. welcome back to dateline. now with the conclusion of the collector, here is dennis murphy. detectives finally had a major break in the investigation. silver coins, worth around the same amount as the ones taken from the terrell home turned up in a local coin shop. surveillance cameras caught the transaction on video. the man looked familiar and if there is any doubt he left a copy of his i.d. >> mark edward porter. this is the real guy. >> that is him. >> but selling a load of coins did not prove mark porter was guilty of murder. mark had an interest in the coin business. >> the explanation is that these were coins mark porter had and a coincidence they were sold after the day the terrells were killed. >> still for police, the friend i.b.m. executive, retired school superintendent and by all appearances a pillar of the community was the prime suspect in the murders of jan and gary terrell. >> i never did like the guy or trust him. thought he was something of a fake. >> gary's brother had a bad feeling about mark and was convinced if mark was the killer the motive was money. >> i think over a period of time he saw jan as an obstacle. >> he didn't show up at the visitation or the funeral. >> conspicuous in his absence or making too much of his nonappearance. >> i think it was obvious there was something going on. >> and his former secretary says that she hated working for mark porter and ended up quitting her job to get away from him. >> he could be a psychopath or something. i said it scares me. >> used that word? >> i did. >> what bothered police is his lack of cooperation. >> he would not give d.n.a. or take a polygraph. >> the suspicious pawnshop transaction and stopping by the terrell house on the night of the murders and a talk about the night of the killings only made them more certain. >> she talked about making a couple of phone calls to mark. she didn't know where he was or what he was doing. but police still needed physical evidence, a d.n.a. sample. they hatched a plan to get one. car is outside the house? >> yes. >> undercover with the officers that were constantly doing surveillance for weeks and weeks. >> nabbing a sample proved more difficult than expected. in all of the weeks officers continued to come up empty. they thought he would be able to get the straw he was drinking his drink with and leave with the straw. >> he knew that you guys had eyes on him. >> it is difficult to know what he knew at that time. an undercover officer followed mark into a automobile change shop. >> he is drinking from the cup and strikes up a casual conversation. >> suspect and the undercover cop. >> obviously mark has no clue what is going on as he is speaking with him. mark's car is done. gets up and leaves and leaves behind the coffee cup. >> police had the sample. less than 24 hours they had the results. >> it is confirmed, a match. the same d.n.a. from the coffee cup is the d.n.a. from the latex glove. >> does your dash board light up? >> can't describe the emotion of it that we will bring resolution to the terrell family. >> two weeks later, armed with search warrants detectives arrested mark porter at his office. >> how did he take that. you got the wrong guy. fussing. >> absolutely not. he said okay and turned around and put his hands behind his back. >> jessica was at work. >> two of my good friends were with me. he was finally caught. >> even the former secretary who didn't like him was horrified. i thought no. no. investigators went back to mark's wife and told gorkys hernandez husband's own story put him at the scene of the crime. that is exactly what mark porter's defense attorney seemed ready to argue. >> he has got a spotless record. five college degrees. has got an outstanding past of good reputation. >> at a bond hearing the defense revealed the strategy, arguing there was nothing suspicious about mark's d.n.a. inside his best friend's house. he was a regular visitor to the house. he would get with gary, put on their gloves and handle the old coins and objects. jurors, benign. do you think that works as a argument in the real world of courtroom drama? >> potentially, yes. >> what about the suspicious coin sale. no way to know for sure the coins came from gary's house. as for the assumption mark porter was a gamblers in debt. you had to wonder whether he owed money to heavy people. >> that was a theory we frequently talked about. >> so the case was not air tight. when mark hired new attorneys to talk about a plea deal, the prosecution was willing to listen. >> what are we willing to risk to try to get the death penalty and can we achieve what we need to achieve without the risk of going to trial. there is a chance of a hung jury and you have to do it again and a chance they come back on a lesser crime. >> both sides agreed and mark porter agreed guilty to two counts of second degree murder and was sentenced to life in prison, no eligibility for parole until he is 82. >> i am shocked, sad and have relief mr. porter will finally be behind bars for presumably the rest of had his life. >> he has to live every day with what he did. every day. all of the lives he destroyed. >> you are saying he has to live in remorse but you have not seen a sign he has remorse. >> that is the only bad part. he still has to sit there. >> jessica has done her best to move on and in february 2015 she and jason finally got married. >> we got married on valentines day. it was a great day it was very sad. my parents weren't there. >> larry took his brother's place and walked her down the aisle. >> she asked me to give her away. should have been my brother's job. >> bittersweet moment. >> it was an honor to do it but it didn't feel right to do it. >> jessica has set up a scholarship in her parents names. as for the offbeat museum of a home, still there with a loving daughter as caretaker. >> that is all for this edition of dateline. see you next time. s edition of dateline. see you next time. i'm craig melvin. >> and i'm natalie morales. >> and this is "dateline." >> it was rough. it was a rough time for the whole community. it hit her town like a lightning bolt. the strange disappearance of carrie olson. >> it was scary. everyone loved carrie. >> it was so painful. >> you reached out to "dateline." >> i did, yes. we started getting people following our page. >> where was she? what was behind this? from far home, a lead. >> i saw the tattoo and said, that is her tattoo, isn't it? >> three caught on camera clues.