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Art student Katelyn Markham was on the cusp of graduating college and engaged to be married when she disappeared without a trace.
“My fiancée is missing,” John Carter urgently informed a 911 dispatcher during an August 14, 2011, call, later featured in Oxygen’s Killer Relationship with Faith Jenkins. “I can’t find her anywhere.”
When police arrived at Katelyn’s townhouse in Fairfield, Ohio, they discovered unsettling clues: Her car was parked outside, and her wallet, containing her driver’s license and $300 in cash, was left on her bed. Her dog, Murphy, was locked in her bedroom, evidently neglected for several hours.
The only item unaccounted for was her cell phone.
For years, the mystery of Katelyn’s disappearance persisted, until investigators shifted their focus to someone within her close-knit circle.
Who Was Katelyn Markham?
Katelyn—who was adopted by parents Dave and Sherri as a baby—was known for her artistic talent and uplifting personality.
In high school, she met John and the two quickly formed a tight bond. John’s stepsister Megan Kunz remembered, “I’ve never seen two people fall in love so quickly.”
The couple had been together five years when in August 2010 John proposed.
“He had given her this beautiful ring,” Megan recalled, “and Katelynn thought it was the most beautiful thing in the world.”
Then, just weeks away from graduating from the Art Institute of Ohio Cincinnati, with plans to move with John to Colorado, Katelynn mysteriously vanished.
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John Carter Details Last Night with Katelynn Markham
With Katelynn finishing up school and John working the night shift as a pizza delivery driver, the couple often had opposite schedules and were still living apart.
John told police the night before she disappeared, they’d spent time together with their mutual friend Brad von Bargen. After Brad left, John wanted to keep the party going and met up with some friends around 11:30 p.m.—an alibi backed up by those same friends—while Katelynn stayed back at her townhouse.
John said he returned to his mom’s house around 1:30 a.m., watched tv and then texted Katelynn a “good morning” text around 4 a.m., before going to bed himself.
According to his account, when he woke up on Sunday afternoon, Katelynn still hadn’t replied to his text, sparking concern. He told police that his worry grew after he drove to her house and saw her car there, but no sign of his fiancé.
During his interview with police, officers noticed that John had what appeared to be scratches along the left side of his neck, which he dismissed as injuries from shaving.
“Where these scratches are at is not a normal place that a man would shave,” Butler County Investigator Paul Newton explained. “It’s below the hairline. It looked to me right away as if those marks were from someone’s hands.”
Detectives began to view John as a person of interest, but there was nothing definitive to tie him to a crime.
It was also still possible that Katelynn had chosen to disappear on her own. Her last outgoing text was to John at 11:36 p.m. on Aug. 13 and the phone stopped pinging shortly after midnight.
Katelynn Markham’s Remains Are Discovered
For months, investigators looked for any sign of the missing 21-year-old, as the community launched search efforts.
Then, on April 7, 2013, a couple looking for scrap materials stumbled upon human remains along a creek in Franklin County, Indiana.
“There was a plastic bag that was over the skull,” Indiana State Police Detective Vance Patton said. “It was a young person, small but we couldn’t tell his sex or anything.”
Authorities later used dental records to identify the remains as Katelynn. Her death was ruled a homicide, but the medical examiner was unable to determine her cause of death.
“I get a knock on the door and there’s two policemen and a pastor,” Dave remembered. “They didn’t have to say a word. I knew what it was about. My heart sank. I started bawling.”
Investigators learned that John’s family owned a farm in Indiana in the same county where the remains were discovered, adding to the suspicion surrounding John. Yet, he continued to deny any involvement.
“I don’t speculate how she got there, because I don’t, I try not to think about that s–t,” John told the detective in a follow-up interview. “I try not to put those images in my head.”
New Witnesses Are Discovered
Without concrete evidence against John, the case went cold until it was picked up again by the Butler County prosecutor’s office in 2020.
Through the renewed investigation, investigator Newton found a witness who believed Katelynn and John had argued at a festival the day before she disappeared and thought they were going to break up. He also found two boys who’d snuck out of their home the night Katelynn vanished, both of who reported seeing John’s car and another vehicle pulling up to the house around 1:30 a.m. and then leaving again a few minutes later.
Yet, John insisted that the boys were lying and told authorities he came home at 1:30 a.m. and then watched television on his computer. John’s computer records did show the episodes played, but strangely the investigator also found evidence that the next morning John had googled plot summaries for the episodes he’d supposedly just watched.
Who Killed Katelynn Markham?
Newton theorized that John killed Katelynn earlier in the night, then went out with his friends to establish an alibi, went home to start the episodes and then returned to Katelynn’s to dispose of the body with the help of an unknown accomplice.
John was arrested in March of 2023, nearly a decade after Katelynn was killed.
The case remained, however, largely circumstantial and given the obstacles, prosecutors agreed to allow John to plead guilty to involuntary manslaughter. He was sentenced to the maximum of three years behind bars.
“It doesn’t seem like three years is near enough for what he did and for what he took from me,” Dave acknowledged. “I could have said no and we could have gone to trial. I believe that he would have still been found guilty. But at this point, I just wanted John to admit it. I wanted John to do time. I wanted John to suffer a little bit.”
