Horse Play
David Davis murder by poison of Shannon Mohr
Farmer David Davis claimed his wife Shannon Mohr was killed in a tragic horse-riding accident. But further investigation would reveal a calculated murder with succinylcholine.
Original air date: August 13, 2001
Posted: January 16, 2023
By: Robert S.
Season 6, Episode 13
When Shannon Mohr, a 25-year-old nurse from Toledo, Ohio met David Davis at a friend's wedding in 1979, she thought it might be love at first sight. Davis, more than ten years Shannon's senior, claimed to be a millionaire and own farms across the country. The couple immediately began a courtship, and after only eight weeks, they married.
The newlyweds quickly moved to Davis' farm in Hillsdale, Michigan and bought two Tennessee Walking Horses. David and Shannon loved riding their horses in the wide open, rural area with Shannon's nephew and their dogs. They'd often visit their kindly neighbor Dick Britton on his farm and spend time with his son. For the first half of 1980, Shannon was living her best life.
On a warm July day, David and Shannon visited Britton on his farm, and David helped Dick service some faulty farm equipment. Less than an hour later, the couple continued their ride and ended up in an isolated field. Under the pretext of having sex, David encouraged Shannon to dismount and get comfortable– the couple often made love outdoors.
Back at the Britton farm, Dick was alarmed to see David Davis galloping back without Shannon. He seemed frantic and pleaded for Dick's help. David claimed Shannon had been thrown from her horse and had struck her head on a rock. Her condition seemed severe. David and Dick raced back to the location where Shannon laid motionless, and them men carried her to Dick's car. They raced to the nearest hospital.
Doctors attempted to resuscitate Shannon, but she never regained consciousness. She was declared dead, and David notified her parents in Ohio. Robert and Lucille Mohr immediately came to Michigan to see their daughter and to console their son in law. Shannon was interned back in her hometown of Toledo, and David Davis' parents attended the funeral.
While talking to David's parents, the Mohrs learned much of what they believed about their deceased daughter's husband had been fabricated. He was by no means a millionaire, and he'd been hiding the fact that he already had two daughters from a previous marriage. This led Robert and Lucille to question the already suspicious circumstances of their daughter's untimely death. They would persuade investigators to reconsider the case and even exhume Shannon's body for an official autopsy. But would it be enough to prove murder?
The Facts
Case Type: Crime
Crime
- Murder
Date & Location
- July 23, 1980
- Hillsdale County, Michigan
Victim
- Shannon Davis (Age: 26)
Perpetrator
- David Davis (Age: 37)
Weapon
- Poison: Succinylcholine
Watch Forensic Files: Season 6, Episode 13
Horse Play
The Evidence
Forensic Evidence
- Report: Autopsy
- Report: Toxicology
Forensic Tools/Techniques
- Mass spectrometry
Usual Suspects
No Evil Geniuses Here ?
- Scene staging: Unconvincing accident evidence
Cringeworthy Crime Jargon ?
- None uttered in this episode
File This Under... ?
- Body exhumed
- Keep it in the family
The Experts
Forensic Experts
- None featured in this episode
Quotable Quotes
- "She was a very good student in school, and she said when she was in first grade, because she went to a Catholic school, ‘I’ll be a nun, or I’ll be a nurse.’ And she became a nurse." - Lucille Mohr: Shannon’s Mother
- "Ya know, her mother was crying and Bob was crying, so I stood right up and yelled at him, I said, ‘Dave, that’s her folks,’ [and] I said, ‘Nobody knows her out here.’ I said, ‘Let them take her back to Toledo and bury her there.’ I said, ‘There people will come to her grave and put flowers on it.’ I said, ‘She don’t know anybody here.’ And he backed down and said, ‘Okay.’" - Dick Britton: David and Shannon’s Neighbor
- "So, the next morning we’re sitting at my table, and he wants to know about the neighbor. He said, ‘Does the neighbor still want to sell his farm?’ And I said, ‘Huh?’ And he said, ‘Never mind.’ And I’m thinking, ‘How can you be thinking of buying a farm the next morning after your wife died?’ Then he left and that just kept working on me. I kept thinking, ‘What… that don’t sound right,’ ya know?" - Dick Britton: David and Shannon’s Neighbor
- "Number one: This young lady actually fell from a horse and struck the only rock around, squarely, and it really is an accident. Or number two: He killed her. And the only way in my opinion for him to get her in a position where he could slam her head into that rock was to have her completely immobilized. So, we wanted to look at the possibility that she was drugged at the time; something that would paralyze her but leave her heart still pumping and still, and she’s still alive." - Don Brooks: (Ret.) Michigan State Police
- "She [a tipster] called, and she wanted to tell me about an individual that she thought could be David Davis. She knew him by a different name, however she was very very reluctant to get involved. She was in fear of her own life." - Don Brooks: (Ret.) Michigan State Police
- "We know that he courted and dated several women before Shannon and asked each of them to marry him in an extremely short period of time. [In] something like 14 months, he asked five different women to marry him. The first one who said ‘Yes’ became his victim." - Mark Blumer: Prosecutor
TV Shows About This Case
- Victim of Love: The Shannon Mohr Story (1993 TV Movie)
- Happily Never After: Gallop to the Grave (s02e03)
- American Justice: The Perfect Murder: The Shannon Mohr Story (s08e20)
Last Words
When planning to catalog this episode, I briefly became confused by another case where the perpetrator was also called David Davis. I knew one was an alias, and a quick search showed I was remembering a pseudonym for Albert J. Walker from the episode Time Will Tell (s05e15). By all accounts, this episode's David Richard Davis was in fact the fraudster and murderer's real name.
I was curious of the events' broader timeline, so here's my best attempt at aligning the key events in this case:
- September 1979: Shannon Mohr (25) meets David Davis (36).
- November 1979: Shannon and David get married and move to Michigan.
- July 23, 1980: David Davis kills Shannon and stages her death as an accident.
- July 30, 1980: Robert + Lucille Mohr (Shannon's parents) and Dick Britton go to the police with their suspicions that David murdered Shannon.
- Late-August 1980: Shannon's body is exhumed for a full autopsy – no evidence of foul play is identified.
- Early 1980s: Researchers at the Karolinska Institutet have success detecting succinylcholine in human tissue.
- February 1981: David Davis has sold his Michigan farm and is living on a boat in the Bahamas with a new girlfriend.
- 1981: Shannon's body is exhumed for a second time to examine her tissue for evidence of succinylcholine poisoning.
- October 13, 1981: Grand jury issues a first-degree murder warrant for David Davis.
- December 28, 1988: Episode of Unsolved Mysteries featuring David Davis is re-aired.
- January 6, 1989: Davis is arrested near the Pago Pago airport in American Samoa after investigators receive a viewer tip.
- November 1990: David Davis goes on trial for Shannon's murder in 1980.
- December 5, 1990: Davis is convicted of first-degree murder and receives life without parole.
(Thanks to this fandom.com article for some date information about the charges, trial and conviction.)
Interestingly in Forensic Files's sixth season, this episode aired only one week after Whodunit (s06e12). Of course, that case saw Kimberly Hricko murder her husband Stephen by injecting him with succinylcholine. She then staged the scene to look like he'd died in an accidental fire. The last scene of the episode talks about the advances made by scientists at the Karolinska Intitutet that led to investigators' ability to detect succinylcholine in human tissue, even after embalming. But this ends up describing an incongruent timeline: Toxicologists using these testing protocols were able to detect succinylcholine in Shannon Davis' tissue in the early 1980s. But subsequently, the procedure didn't seem to exist yet during the Stephen Hricko case in the last 1990s. What gives?
The Mohrs' suspicion was not surprising
There were several red flags in David Davis' behavior on July 23, 1980. On the couple's typical horseback rides, their dogs and/or Shannon's nephew would regular accompany them. And Dick Britton's son would often ride back to the Davis farm which Shannon encouraged on this fateful day. But David Davis declined any additional company since his devious plan was already underway.
Then, against Shannon's parents' wishes, David Davis wanted his deceased wife's body cremated. Dick Britton supposedly interjected, telling Davis that Shannon deserved a grave back in her hometown of Toledo, Ohio. Honoring her parents' request, David Davis acquiesced.
Believing Shannon's death was a tragic accident, the investigators didn't consider the scene with much skepticism, despite the fact that there were several irregularities. For one, the grass around Shannon's body had been matted down. This was hard to explain by a fall from her horse, even if David had attempted to render aid. Her unbuttoned blouse and shoeless feet were even harder to rationalize. It's unwise and unsafe to ride a horse without shoes, and Davis would've had to reason to remove them after her supposed fall.
Possibly most suspicious about the scene of Shannon's death was the sole rock at the location. It was stated to be the only rock within 100 yards. It is possible to be unlucky enough to be thrown from a horse, hit your head squarely on the only nearby rock, but then to have this single blow cause your death seems a coincidence too far. It was believed that Shannon must have been subdued (drugged by the succinylcholine), and Davis then struck her on the head with the rock. But then ask yourself: Did David Davis get lucky that the clearing already sported the convenient rock? Or did he possibly bring this lone stone to the scene along with the syringe and poison?
Short on form, long on content
In a 22-minute format, each episode simply doesn't have time to address all the possible loose ends and questions that might arise. For example, Davis attacked Shannon, and he rode back to Dick Britton's farm for "help". Then the two men raced back to the scene of Shannon's "accident". If Davis stayed on his horse, how did Britton travel? And how did the men transport Shannon to Britton's car to get to the hospital?
Around the episode's 6:35 mark, Lucille Mohr comments on seeing three deep scratches on David Davis' hand (when he "ran his hand under my face"). This made for an interesting quip, but it seems the examination and questioning of David Davis disregarded this potential evidence. The scratches are never mentioned again.
During the autopsy, the majority of bruises were found on Shannon's left side. This supported the idea that Shannon had likely fallen on her left side, so the investigators first looked at the bruising on her right side for signs of a possible injection site. But if there was no actual fall in the first place, the logic behind focusing their search on Shannon's right side seems misguided. Ultimately, the injection sites – found by the higher concentrations of succinylcholine – were on her right shoulder and right wrist.
Finally, who was the ex-girlfriend that provided the tip in 1988? He'd been using the alias "David Myer Bell" while dating this informant. While this ex-girlfriend from after Shannon's murder was afraid to get involved in his capture or trial, other exes weren't. One ex during the trial testified that David Davis had described a murder to her where the perpetrator had used succinylcholine. This was several years before Shannon's murder. Another ex-girlfriend had dated Davis both before and after the murder. He kept distance from this ex during the year prior to Shannon's murder, claiming he was doing something "dangerous".
David Davis on the run for over eight years
Davis was holding out for the investigation into Shannon's death to wrap up so he could collect the $330k from her life insurance. But when an indictment for murder was handed down instead, Davis went on the run. For over eight years, David Davis eluded police. He spent time in California, Alaska, and Hawaii (according to our episode) and in Florida and Haiti (according to other sources). Of course, he was apprehended in American Samoa where he'd been laying low in the tiny village of Tafuna. He'd remarried a Samoan woman in 1986 and told her that his previous wife had died in a "tragic accident". Did he tell his new wife about his two daughters?
More importantly, had David Davis taken out any life insurance on his new, Samoan wife? Perhaps his vocation as a bush pilot provided enough income and Davis was no longer victimizing women for profit. Rather than a bush pilot, the fandom.com article indicates he was "a chief pilot for Samoa Air, a small commercial airline." Ultimately, Davis is lucky he didn't continue to hide out in Honolulu, as he'd surely have ended up captured by Duane "Dog" Chapman.
The episode concluded with another remark from Lucille Mohr. She practically blamed herself for her daughter Shannon's death by not being able to see through David Davis' lies. This castigation of herself is unfair – nobody uncovered Davis' web of deceit in time to save Shannon. Between being a millionaire, owning multiple farms and the rest of his fabrications, it's possible everyone just wanted to believe David Davis was as good as he portrayed himself. I also feel people in general were less skeptical, less cynical then, over four decades ago, than we are now.
Where is David Davis now in 2024?
In late-1990, David Davis was convicted of the first-degree murder of Shannon Mohr's and was sentenced to life in prison without parole. He served nearly 25 years with the Michigan Department of Corrections. On November 9, 2014, David Davis died at the Duane L. Waters Health Center in Jackson, Michigan. He was 70 years old.
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Robert S.
I've been a fan of Forensic Files since the show's inception, and it is still my favorite true crime series. I have seen every episode several times, and I am considered an expert on the series and the cases it covers.- Unholy Alliance (s10e24) Posted: December 24, 2023
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