How Police Tracked Down a Serial Killer Who Got Away with It for Years by Preying on the Elderly

Mar. 15, 2025

Billy Chemirmir.Photo:Tom Fox/The Dallas Morning News via AP

Tom Fox/The Dallas Morning News via AP

Mary Bartel, 91, was an early riser.

On the morning of March 19, 2018, the feisty grandmother woke up at 4:30 a.m., took her blood pressure and then went for her daily walk around the grounds of the Preston Place Retirement Community in Plano, Texas.

She then drove to a 6:30 a.m. church mass before returning to her first-floor apartment she’d once shared with her husband before he passed away.

Bartel was at her computer writing an email when she heard someone incessantly knocking on her door.

“I opened the door and I saw this man with his green rubber gloves on,” she later told authorities. “I tried to push back but I’m 91-years-old and he is young and muscular. And he just said, ‘Don’t fight me. Just get on the bed.'”

Fearful, Bartel complied.

The man then grabbed a pillow and attempted to smother her — and the horrific story is the subject of the upcoming episode ofPeople Magazine Investigates. Titled “A Serial Killer’s Playbook,” the episode premieres Monday, November 25 at 9/8c on ID. (An exclusive clip is shown below.)

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“I felt as though I could not breathe,” she said. “I thought I would die. I am not afraid to die but I didn’t want to die that way.”

Convinced that Bartel was dead, the man stole some jewelry before fleeing the retirement complex.

Chemirmir victims Lu Thi Harris, Leah Corken, Mary Brooks.AP Photo/LM Otero, Tom Fox/The Dallas Morning News/Pool via AP

AP Photo/LM Otero, Tom Fox/The Dallas Morning News/Pool via AP

Billy Chemirmir.Dallas County Jail

As she was transported to the hospital, she regained consciousness and told authorities about her brutal ordeal.

Ultimately, the attack on Bartel changed everything for law enforcement.

Before the attempted murder of Bartel, more than six women died at the same retirement complex, but police assumed they’d died from natural causes.

Police canvassed the complex and learned that the son of a resident reported a stranger loitering in the parking lot a few days earlier.

The witness had written down a license plate for the stranger’s Nissan Altima.

Investigators ran the license plate number and discovered the vehicle was registered to Billy Chemirmir, a former health care worker who’d moved to the United States in 2003 from Kenya.

The following day, on March 20, Chemirmir was arrested in the parking lot of his Dallas apartment complex after authorities watched him toss into the dumpster a distinct red wooden jewelry box with Asian markings.

Legal papers found in the jewelry box tied him to the murder of 81-year-old Lu Thi Harris, who was found smothered to death with a pillow in her bedroom.

In total, Chemirmir was charged with the murders of 22 seniors between 2016 and 2018.

He was convicted of killing two elderly women, including Harris,NBC5reported.

People Magazine Investigates: A Serial Killer’s Playbookpremieres Monday, November 25 at 9/8c on ID.

source: people.com