and just somehow crossed paths with tanya and jay. narrator: in june of 2019, william talbott was convicted of aggravated murder and sentenced to two consecutive life terms without the possibility of parole. his case is a forensic first. the suspected golden state killer was exposed by genetic genealogy. in talbott's case, in a legal precedent, the genetic genealogy evidence was presented to a jury and helped put him behind bars. this is a game-changer for investigators, for forensic scientists, for prosecutors. genetic genealogy is the best crime-fighting tool that's come along since dna came along. moore: in jay and tanya's case, genetic genealogy was able to develop a suspect

who had never even been considered previously. william earl talbott really was the first good suspect they ever had in all these years of investigating the case. ♪ narrator: up next, this medical professional was obsessed with staying healthy. herbal supplements were her big thing. she was always trying to have everyone healthy. narrator: but in a matter of days, what looks like a disease cuts her down. whatever it is just came on, and it killed her. narrator: is she dead from natural causes... [ flatlining ] ...or something more sinister? this is probably the most bizarre case that i've ever worked on. ♪ ♪

narrator: utica is so far north in new york state that it's closer to canada than to new york city. locals are proud of their past. but like a lot of people in rust belt communities, they face an uncertain future. it's just a beautiful city. was a beautiful city. it's gotten its little hairy parts now, but it was a beautiful city. narrator: bill and mary yoder's chiropractic business was one of the busiest in the area, which came as no surprise to their hundreds of loyal patients. phelps: mary and bill -- they build up this chiropractic business, and they turn it, really, into a family business that everybody in utica really looks to as, "this is the place to go." narrator: the yoders had been married for nearly 40 years and had three grown children. on july 20, 2015, bill had the day off while mary worked with clients. but late that afternoon, mary got sick to her stomach,

and this didn't appear like an ordinary bug. phelps: patients report she's running in and out of the bathroom, something she never did. narrator: once mary got home, things got worse and then spiraled steadily downward. the next day, she went to the hospital. phelps: she's in the e.r., and she is severely ill. her legs are swelling. her skin is turning green, basically. they can't figure out what's going on. narrator: mary was known for taking a lot of supplements. phelps: she lives a kind of green lifestyle. she only puts healthy things in her body. narrator: could one of those supplements have caused her illness? baffled doctors didn't think this was likely but couldn't be sure, and testing on those products could take time, which they didn't have. they do not have a firm grip on what has taken place with her. narrator: that night, mary rebounded, but not for long.

soon, her whole body, including her heart, started failing. less than 36 hours after being admitted... [ flatlining ] ...she was dead. it all happened so fast that her family and many in the community were blindsided. groah: i mean, you're shocked. i just saw her. she just worked on me. she was fine. so, i was in shock. she was healthy when i left. how did mary go from the healthiest person in the family to dead? narrator: that question confounded doctors, and mary's autopsy provided limited answers. doctors discovered a physiological process called apoptosis. vannamee: mary yoder's cells appeared to be attacking themselves, and that is an indication of a person who has either undergone a strong dosage of chemotherapy or had poison introduced into their body.

narrator: mary certainly hadn't undergone chemotherapy. in fact, just a few days earlier, she'd been in perfect health. standard toxicology screens all came back negative. mary's case didn't make any sense to anyone. so, the medical examiner's office is stuck. they don't know what killed this woman. vannamee: they were looking at every possible angle, and they just did not have a conclusion. narrator: one test result ultimately did provide the answer to what killed mary yoder. but that result also raised a host of shocking questions about how it happened and who might be responsible. ♪

narrator: just three days before her death, mary yoder was the picture of health, but her autopsy showed a ravaged body. her system had sustained the kind of damage suffered by someone

undergoing long-term intensive chemotherapy. she wound up having multi-system organ failure over a very short period of time. narrator: everything pointed to some type of poison. so the medical examiner reached out to clinical toxicologist dr. jeanna marraffa with the upstate new york poison control center. i was thinking, "could there be something terribly wrong with her vitamins and supplements and it be a contaminant in there?" and as those were quickly ruled out, then i didn't know the source. narrator: mary's symptoms were distinctive -- rapid organ failure, large-scale cell death throughout the body, cardiac arrest. [ flatlining ] it usually signifies that there's some kind of toxin in the body. narrator: doctors theorized about a possible culprit, a drug called "colchicine" that's normally used to treat gout. scotti: jeanna marraffa looked at all the symptoms, looked at the medical charts, and said, "i think you need to test for colchicine."

marraffa: it's not very common. i've probably only had 15 colchicine cases in my career. narrator: colchicine works in ways similar to chemotherapy. it stops the normal process of cell division, which is good if you have something like gout. if you don't, it can be a problem. it's potentially very toxic, so it's used in very low doses and usually monitored clinically if people are taking it. narrator: mary's blood sample was subjected to a process called liquid chromatography tandem-mass spectrometry. the first step is to separate whatever is not blood from the rest of the blood sample. once those compounds are separated, they can actually enter the mass spectrometer. narrator: all compounds have a specific chemical signature that, once isolated, produce distinctive waveforms in the mass spectrometer. this is done based on the chemical characteristics and the mass of the compound.

narrator: in this case, the resulting waveform was measured against the waveform of a known sample of colchicine. mary yoder's blood was found to have unusually high concentrations of the drug. it certainly was a large amount compared to what we see in a clinical therapeutic application. marraffa: i received a phone call, and he said, "you're never gonna believe it, but the colchicine level is through the roof." and i said, "are you sure?" and he said, "yes, i have it right here." narrator: mary yoder had essentially overdosed on colchicine. was her death an accident, a suicide? no one thought mary was suicidal. and there are a lot of easier and less painful ways to kill yourself than using an obscure gout medication. phelps: no one in the family has gout. no one they know has gout. mary certainly didn't have gout. how did the colchicine get into her body and kill her?

narrator: that question landed right in the laps of local police because mary's death didn't look like suicide or an accident. phelps: what does that leave you? that leaves you with homicide. that leaves you with somebody deliberately put colchicine in something that mary ate or drank that day to kill her. narrator: but who and why? in november of 2015, the sheriff's office opened a criminal investigation. groah: a detective came to my door, and he told me that he was investigating a murder. and i'm like, "whose murder?" ♪ and he said, "mary yoder." and i said, "she wasn't murdered. she just di--" he said, "no. we believe she was murdered." narrator: by this time, four months had passed since mary's death, and detectives soon learn that a lot of unexpected things had happened with the yoder family in those four months.

just because you're not a great husband doesn't mean you're a murder. ♪

narrator: small towns are pretty much the same the world over. people know each other, tend to look after each other, and oftentimes are aware of each other's business. in bill and mary yoder's town, local tongues started wagging shortly after mary's death. we become aware that bill yoder is involved in a relationship with one of mary yoder's older sisters. narrator: their relationship apparently began soon after mary died. and that obviously sent up some red flags to us that that had been the motive for killing mary yoder. narrator: and statistics back up the suspicion. in the u.s., nearly three women are killed every day by current or former romantic partners.

phelps: the first person investigators are gonna look at is the husband. so, if mary yoder is a bull's-eye, the first ring around that bull's-eye is bill yoder. narrator: bill denied any involvement in mary's murder. as police check to see if he could have purchased the murder weapon, colchicine, the case took yet another bizarre turn. an anonymous letter arrived at the medical examiner's office. an identical letter was sent to the sheriff. whoever wrote these letters had inside information on the investigation. the letter-writer specifically named what the toxin was, colchicine, which, at that point, very few people knew that. narrator: the letter-writer was in no doubt about who killed mary yoder. phelps: it points specifically to adam yoder, the son. and it also claims that adam yoder had motive

to kill his mother -- that he was going to get some money out of this. narrator: the letter said the bottle of colchicine, the murder weapon, was under the front seat of adam's jeep. adam was called in for an interview with police and was stunned when told he was a person of interest in his mother's murder. we tell him that we would like to look in his jeep, under the seat, right where this letter directs us. you could have probably tipped him over with a father. narrator: a shaken adam yoder asked for an attorney, who promptly told him to consent to the search of his jeep. and, sure enough, just as the letter indicated, a bottle of colchicine was found under the front seat. vannamee: i wanted to see his reaction, and i can recall him smoking a cigarette, and the cigarette almost fell out of his mouth, like he was in such shock of what we had pulled out of his truck. narrator: with the bottle was a receipt for the colchicine purchase, and it had an e-mail address.

adam said he had no idea how the drug got in his jeep and that this e-mail address wasn't his. he said he'd never seen that e-mail, that wasn't his e-mail, and he'd never used that e-mail. narrator: adam told police he thought he was being framed, and they didn't think this was so far-fetched. phelps: this guy drives his jeep to the sheriff's department with the colchicine that killed his mother? "hell, no," they're saying. we don't buy that. who would keep the toxin in their car and then bring their car up to the sheriff's office and consent to the search of it? it didn't make any sense. narrator: amid all this misdirection, investigators were coming to an unavoidable conclusion. whoever wrote the letter was probably the person that killed mary yoder. narrator: the investigation now centered on the envelopes with the anonymous letters, which were typewritten, the bottle of colchicine,

which was found inside a small cardboard sleeve, and the prescription receipt with the e-mail address. everything was tested for dna, and when those results came back, investigators got yet another shock. you know what is found on that bottle and the cardboard? female dna. narrator: and that dna was not mary yoder's. could the dna reveal who had handled this highly unusual murder weapon? which now throws this case into an entire new direction. ♪

narrator: the envelopes containing the anonymous letters implicating adam yoder in his mother's murder were typewritten -- not exactly a regular occurrence in 2015. the office in the yoders' business had a typewriter. detectives were curious.

bill says to him, "look, you don't need a search warrant. go. carte blanche, go in that office. take whatever you want. i don't care. i'm an open book." narrator: analysts dismantle the typewriter, which only four people had access to -- bill and mary yoder, adam yoder, and the office receptionist, kaity conley. scotti: the examination of the typewriter ribbon really went back to old-school police work. vannamee: the cartridge was taken apart, and the used ribbon was cut into approximately 2-to-3-foot lengths and placed on a white posterboard, and you could actually read every keystroke that that typewriter had made. narrator: and those keystrokes showed the addresses of the medical examiner and the sheriff's office -- the destinations of the anonymous letters. this proved the envelopes that contained the letters implicating adam yoder had been typed on this machine. 22-year-old kaity conley was confronted with this evidence

and admitted straight away that she was the letter-writer. i specifically asked kaity conley, "did you write us the anonymous letter?" and her response to me is, "you can't protect me." narrator: kaity said she was terrified of adam yoder, that adam killed his mother, and that she wrote the anonymous letters to expose him. she made adam seem out to be a monster. narrator: it turned out that kaity and adam yoder had dated off and on for a few years. but about a year before the murder, adam broke off the relationship. kaity had a reputation back in high school for getting back at boyfriends. you know, the old scorned lover -- that was her. adam broke up with her.

what is she going to do next? well, she's gonna take away from adam the thing that he loves the most. that's his mother. narrator: kaity told detectives that she knew nothing about colchicine, but that adam did. ♪ the keys seem to lie in the e-mail address found with the bottle of colchicine, an online record created when the drug was purchased over the internet. vannamee: whoever has control of that gmail account is the one that purchased this colchicine. narrator: the e-mail address was on a google account. the company couldn't provide the name, but they could provide what's called an internet protocol, or ip, address. martino: it's very similar to the phone system. only one phone can have a specific phone number at any time. otherwise, it doesn't work. narrator: the internet service provider was able to backtrack

when e-mails were sent from that ip address, and gps could also give a good idea where the e-mails had been sent from. by knowing when and where they were sent, investigators had a good idea of who had sent them. there are only two devices that have any nexus to that gmail account at all. one of them is kaitlyn conley's cellphone, and the other is the computer at the chiropractic office that kaitlyn conley uses. narrator: analysts searched kaity's devices and found that large amounts of data had been deleted from her cellphone shortly after mary's murder. however, in a twist that would upend the investigation, adam claimed he and kaity briefly reunited after mary's murder. during this period, kaity backed up her phone on adam's computer, and almost all her deleted data was there.

martino: it was the light-bulb moment. it brought back thousands of pictures and images and screenshots. scotti: there was -- several searches had been done regarding colchicine. one talked about the cardiac impact of colchicine. another talked about how you treat people who have been poisoned by colchicine. narrator: by this time, the unknown female dna found with the bottle of colchicine in adam's car was matched to kaity conley. in june of 2016, she was charged with second-degree murder. at trial, prosecutors argued that she had planned mary yoder's murder for months. this is a well-planned-out, cold, calculated thing. lisi: i think initially what her intent was -- "i'm going to kill mary yoder. that'll bring adam back to me. i'll get back in his good graces," and, in fact, that's really what happened shortly after the homicide. narrator: prosecutors say kaity was able to buy the colchicine online

by going through the yoders' chiropractic business. the evidence appears to indicate she spiked a protein shake with so much colchicine that mary yoder overdosed almost immediately. when kaity tried to throw off investigators by writing the anonymous letters, she didn't realize the typewriter could be tied back to her. she also didn't know that the e-mail address, the one she thought could keep her anonymous, would not only reveal her identity, it would show how she searched online for the colchicine, a murder weapon she thought no one would ever discover. finally, despite all her attempts to frame adam yoder for the murder, kaity's dna, not adam's, was on the key pieces of evidence. groah: i had such a tough time thinking that she would do that because she was such -- she was such a sweet girl in that office.

i mean, i talked to her all the time. there's no way i believed that she would do it. narrator: she wasn't the only one. the jury in kaity's first trial couldn't reach a verdict. lisi: i just remember honestly going out, walking to my car, crying for about two minutes in the parking lot, and then saying, "okay, that's it. that's enough. it's time to get back to work and see if we can put this case together again." narrator: and that's what happened. in a second trial, in november of 2017, kaity conley was found guilty of first-degree manslaughter and sentenced to 23 years in prison. she still maintains her innocence, but the dna, the evidence from the typewriter, the attempted frame-up, the web searches, and the purchase of the colchicine all pointed in one direction -- to a young woman with a bizarre motive for murder. vannamee: a lot of people have had a difficult or a tough time accepting the fact that kaitlyn conley is guilty for the death of mary yoder.