Plastic sheeting used to wrap remains of woman killed in 2011 became investigators' focus

When investigators executed a search warrant on the home of John Carter's mother in February, they were looking for plastic sheeting used in construction and landscaping, a newly unsealed search warrant shows.

That's the same type of material Katelyn Markham, Carter's fiancée, was wrapped in when her remains were found roughly two years after her August 2011 disappearance, the document states. Her skull was wrapped separately in a plastic shopping bag.

That evidence, which helped detectives zero in on Carter as their chief suspect in Markham's killing, was revealed in case documents that became public Tuesday detailing the investigation.

Investigators believed Carter, 35, obtained the plastic sheeting from his mother's Fairfield home and used it when he disposed of Markham's corpse, the document states, adding the material is used to create garden beds or to line basements and crawl spaces.

While the rolls of sheeting are usually purchased by contractors, the court document states, the remnants are often left with the homeowner after a project is finished.

A roll of landscaping material, located in the property's shed, was among the items recovered during the search, the document shows, though it's not clear if that material matches the sheeting wrapped around Markham's remains.

Prosecutors said cryptic writings belonging to Carter were also recovered from the home.

Markham disappeared on Aug. 13, 2011. She was last seen between 11:30 p.m. and midnight when Carter said he left her Dorshire Drive home. He was arrested last month and indicted on two counts of murder in connection with her death.

Her remains were discovered near Big Cedar Creek in Indiana, roughly 30 miles from her home, by a couple looking for aluminum cans. Investigators ruled Markham's death a homicide and concluded that she died around the time of her disappearance, the document states.

A forensic anthropology report indicates the location where Markham's remains were discovered is different from where they were first left, prosecutors said.

Carter would have been familiar with the area where Markham's remains were recovered, the search warrant said, because it was nearby the routes from his home in Butler County to the properties his father owned in Ross Township and Laurel, Indiana.

Three polygraph examinations indicated "deceptive responses" from Carter as he denied his involvement in Markham's death, the document says.

When police interviewed Carter the day after Markham's disappearance, investigators noticed and photographed red, vertical scratch marks on the left side of his neck, the search warrant states. He initially said the scratches came from a razor but later told police he didn't know how he got them.

It was Carter who called 911 on April 14, saying he had not been able to reach Markham throughout the day. He told Fairfield police that he let himself into Markham's townhouse and found no signs of her. Her purse and keys were inside the apartment but her cell phone was missing. Markham's car was parked outside and her dog wasn't locked up, Carter said.

When Markham disappeared, she was less than a month from finishing her graphic arts degree at the Art Institute of Ohio-Cincinnati. She also was nearing the first anniversary of her engagement to Carter.

Carter said he and Markham were planning to move to Colorado that November. However, several witnesses told investigators Carter and Markham's relationship had become strained in the months leading up to her disappearance, the search warrant states.

Markham even confided in one witness that she was unhappy with her engagement to Carter and she felt "trapped in the relationship."

The release of these previously sealed court records is the first detailed outline of the decade-long investigation into Markham's killing.

Carter posted a $1 million bond earlier this month. As a condition of his bond, he must wear a GPS monitor that will track his location.

He is scheduled to stand trial in June 2024. Jonathan Palmerton, 35, who's charged with perjury in connection with the case, will go on trial in August.

In court filings, Carter's lawyer, Christopher Pagan, said his client has no criminal record or juvenile adjudications. Pagan noted that Carter has lived his entire life in Butler and Hamilton counties.

"The offense occurred in 2011," Pagan said. "The defendant (Carter) has remained in the area since then and cooperated with law enforcement for over a decade without fail."

Enquirer media partner Fox19 contributed to this report.