John Carter called Katelyn Markham the love of his life. Then he was charged with her murder.

John Carter seemed desperate to find his missing fiancée.

On the night of August 14, 2011 – less than 24 hours after Katelyn Markham was last seen in the Cincinnati suburb where she lived – Carter called 911 and reported her missing. In the months and years that followed, he repeatedly provided the police with information. He addressed local and national media pleading for her return, and in an interview he told NBC's “TODAY” show that he still calls her daily on her cell phone.

“This is everything I hoped for,” he then said.

For more on this case, tune in to The Butterfly on “Dateline” tonight at 9 ET/8 CT.

But last year — more than a decade after Markham's remains were discovered in a makeshift Indiana landfill — Carter's self-portrayal as a desperate partner failed with a stunning development: He was charged with two counts of murder in Markham's death. Weeks before his death As the trial was set to begin in June of this year, there was more surprising news: Prosecutors had agreed to drop charges if Carter pleaded guilty to the lesser crime of involuntary manslaughter.

On July 18, a judge sentenced Carter, 36, to the maximum sentence allowed under Ohio law of three years.

In an interview with “Dateline,” Butler County Prosecutor Michael Gmoser explained why he decided to file charges against Carter after more than a decade — and why he agreed to drop them in exchange for a felony plea to drop it, which resulted in a far less severe punishment. “I know that there are a number of people who will condemn me for accepting a plea deal that only allows them a three-year prison sentence,” Gmoser said, adding: “It was more important to me to get justice through a guilty plea for Katelyn Markham, whether it was one day, six days, six months, six years or 60 years.”

Carter's defense team and his family did not comment on the agreement. Carter did not discuss the agreement at his sentencing; One of his lawyers said his client has accepted responsibility for Markham's death.

In an interview with “Dateline,” Markham's father, Dave, described the moment he learned of the deal as painful and shocking, but said he understood that a single juror could have prevented a possible conviction if the case had gone to trial . “There was a chance John could walk, and I didn't want that,” he said.

The night she disappeared

When she disappeared, Katelyn Markham, a 21-year-old student known for her bold personality and artistic talent, had been dating Carter for five years and they had been engaged for a year. They planned to move to Colorado, and in a media interview shortly after her disappearance, Carter – then a pizza delivery driver at Papa John's – called her “the love of my life.”

In interviews with police, Carter recounted their last night together. A friend stopped by the Fairfield home where Markham lived before Carter left to meet another friend, according to video of an interview Carter gave to Fairfield police. Markham stayed home, Carter told authorities.

Carter said he went to his mother's house, where he lived, around 2 a.m. and watched a favorite show before falling asleep around 4 a.m., according to the video. When he hadn't heard from his fiancée the next evening, he panicked and called 911.

Investigators confirmed that Carter had attended the meeting, police records show, and found on his computer that he had watched episodes of “White Collar.”

Investigators believe Carter was held accountable that night, according to an FBI report on the case that Fairfield police sought advice from.

But years later, an investigator in Gmoser's office who reinvestigated the case found reasons to doubt Carter's account.

Doubts begin to arise

One possible eyewitness account came from two teenagers who were in Carter's neighborhood early August 14, 2011, the night Markham disappeared. After their skeletal remains were discovered in the landfill nearly two years later, on April 7, 2013, the teens contacted police and told them they had seen something strange at Carter's home, according to summaries of their interviews in the case file .

They had sneaked out to go to a party, they said, and around 2 a.m. two cars slowly pulled up to Carter's house, including one they recognized as Carter's red Ford, according to the filing. None of the cars had their lights on. About five minutes later, one of the teens said, Carter's car pulled out of the garage and the two cars drove off, the filing said.

Rebecca Ervin, The lead investigator who originally investigated the case described her accounts as “suspicious,” in part because Carter's computer activity had traced his whereabouts, according to the filing.

But investigators in Gmoser's office uncovered details that also called this part of Carter's account into question: Carter's online search history from the day he reported Markham missing indicated that he had been searching the Internet for broadcast summaries he had supposedly seen. Gmoser said. Gmoser said he believes Carter read the summaries to create an alibi.

When investigators in Gmoser's office re-interviewed the witnesses who said they saw Carter's red Ford without its lights on, they provided the same report as in 2013 and, in Gmoser's opinion, the one they had They said they saw a crucial piece of evidence that morning that may have linked Carter to the case.

Ervin was “convinced” that Carter was not involved, Gmoser said. “She was wrong.”

Ervin, who still works for the Fairfield Police Department and holds the rank of major, declined to speak to Dateline about the case. In an email, current Fairfield Police Chief Stephen Maynard disputed Gmoser's comments.

Maynard said Carter was never eliminated as a suspect, and he provided what he called a more accurate statement: “Detective Ervin did not believe there was enough evidence to conclude that Carter was responsible for Markham's death.” “, he wrote.

“She has to die”

Gmoser assumed that by early 2023 his investigators and prosecutors had put together a case against Carter that they believed would not get any tougher. On March 13 of that year, a grand jury indicted Carter on murder charges in Markham's death. He pleaded not guilty.

At a subsequent hearing in a Butler County courtroom, Gmoser revealed that investigators had found disturbing poems in Carter's diary: “Deep down, I love her,” he said Carter wrote. “You want to kill her. But I love her. She has to die.”

And, “I know I'll bury the body in the back yard, no, I'll bury it under the trailer and wait for the grass to grow over it before anyone reports it missing.”

In a search warrant canceled in April of this year, prosecutors identified a possible motive for her death. Although Carter had described Markham as the love of his life, “Markham told a friend before her disappearance that she was tired of their relationship and was reconsidering the impending move to Colorado. “Breaking up with John would be a disaster for John,” Paul Newton said , lead investigator for the Butler County Prosecutor's Office, told Dateline.

Prosecutors also learned that a former neighbor of Markham's – their apartments shared a wall when she disappeared in 2011 – recalled hearing an argument in Markham's apartment on the night of August 13, 2011. According to a video of an interview Newton conducted with the woman, she said she heard a woman on the other side of the wall shout “Stop it” – then a thud.

But all the evidence investigators uncovered was circumstantial. There was no forensic, eyewitness or video evidence directly linking Carter to Markham's death, Gmoser said. Prosecutors also couldn't say much about how she was killed.

Although Markham's remains were found and the medical examiner's office concluded she died by homicide, officials were unable to determine a cause of death, according to the files.

A litany of questions remained, Gmoser told Dateline. Was Markham killed in Indiana? Did she go there voluntarily? Did she leave her apartment alone?

“These are all open questions,” he said.

An admission of guilt

Gmoser said no one in his office had spoken to Carter's lawyers about the possibility of a settlement. Weeks before his trial was scheduled to begin this summer, a defense attorney asked prosecutors whether they would consider allowing Carter to plead guilty to a third-degree felony — negligent homicide or causing the death of another through an administrative offense.

“I told him to take it,” Gmoser said. “It happened almost so quickly.”

He made the decision in just a few minutes, Gmoser said, but it developed over months as he “examined every circumstantial evidence of how it would be attacked, as I would have attacked it as a defense attorney.”

“I knew what to expect,” said Gmoser.

Because the statute of limitations has expired on other possible crimes, such as tampering with evidence or desecrating a corpse, manslaughter is the only available charge his office can pursue under the agreement, he said.

Gmoser could have required Carter to provide a report on Markham's death. But that, said Gmoser, would have led to negotiations. And he wanted to be sure prosecutors got an admission of guilt, he said.

“I took responsibility,” said Gmoser. “I’ll take that.”