The Wanglers’ seemingly peaceful life was rocked in 2006 when Kathy Wangler was found unresponsive by her husband, Mark. An inquiry that lasted about three years culminated in Mark’s arrest for what the authorities believed to be murder. Investigation Discovery’s ‘Til Death Do Us Part: While You Were Sleeping’ chronicles a complex case that involved a fair bit of circumstantial evidence that led to a conviction. So, let’s find out what happened then, shall we?
How Did Kathy Wangler Die?
Kathleen was born in May 1958 as the oldest of five siblings in Mercer County, Ohio. Growing up, she was close to her family and looked out for everyone. Kathy got married to Mark Wangler when they were in their twenties, with her helping him pay for medical school. They had two sons, Nathan and Aaron, and during her thirties, Kathy went back to school to get a business degree. The family settled into a comfortable life in Lima, Ohio, at the time.
At around 5:17 AM on September 4, 2006, Mark called 911 to report that his 48-year-old wife had a seizure. She had been sleeping in the upstairs bedroom while Mark was in the downstairs master bedroom, woken up by the carbon monoxide alarm going off. The authorities arrived to find Kathy with no pulse, and she was pronounced dead sometime later. The cause of death was acute carbon monoxide poisoning, with the police concluding their investigation by ruling it a homicide.
Who Killed Kathy Wangler?
Mark, an anesthesiologist, told the police that he woke up and felt the classic signs of CO poisoning: disorientation and nausea. He claimed that the water heater had been faulty and caused CO to flow through the house’s air ducts. Mark had to leave for work early while Kathy stayed up, so they slept in different bedrooms that night. It seemed like an accidental death, but the authorities weren’t sure that was the case. However, they needed more evidence to prove otherwise.
In the months after Kathy’s death, Mark began dating Esther Erkman, a friend, and they married about 14 months after the incident. Afterward, Mark admitted that his marriage to Kathy had been rocky during the later years. According to him, they hadn’t talked about separation but were seeing a marriage counselor. Mark further stated that Kathy had credit card debt and a secret bank account. Kathy’s sister, Diane, claimed the mother of two admitted to things being bad in her marriage.
Kathy’s friend, Sherry, said, “She had told me that her husband was out to destroy her – financially, emotionally, psychologically, in the community, at her church. That he was in the process of working to destroy her.” The authorities were also suspicious of Mark’s behavior in general. They thought it was too convenient that Mark was sleeping in a different room with the windows open when Kathy died. Also, she was confirmed to be dead about an hour or two before the 911 call.
During the investigation, gas company employees checked the water heater and the furnace but couldn’t find anything wrong; no high levels of CO emanated from the appliances. This cast doubt on Mark’s story of the heater malfunctioning. The prosecution believed he killed Kathy to avoid divorce because that was not ideal for a religious man in a religious community.
They considered the possibility of car exhaust being intentionally routed into the air ducts to cause CO poisoning. There was also the evidence from Mark’s journal where he talked about marital problems with Kathy. An excerpt read, “Thoughts of suicide are a little strong again. Satan is attacking in a new way, this time using car exhaust.” Despite no clear answer to the source of CO, the case went to trial.
Where is Dr. Mark Wangler Now?
At the trial, Mark’s lawyers contended that his behavior when he found Kathy could be explained because his oxygen levels were low and said that the death was an unfortunate accident. Nevertheless, in March 2011, Mark was found guilty of aggravated murder and was sentenced to 25 years to life in prison. Kathy’s mother, Sarah, said to him in court, “Mark, you senselessly robbed Kathy of her many most precious moments; her two sons, Nathan and Aaron. She worshipped them, did everything in the world for them.” Prison records indicate that Mark remains incarcerated at the Marion Correctional Institution in Ohio. He will be eligible for parole in 2036.
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