Police Thought Deaths of 22 Seniors Were from Natural Causes — But Now They Suspect a Serial Killer

Three weeks before Christmas in 2017, Diane Delahunty spent the day visiting with her grown children at Preston Place Senior Living Apartments in Plano, Texas. After lunch, her children went home, leaving the vibrant 79-year-old in her comfortable upscale apartment. The plan was for her kids to return later in the week to help her decorate her Christmas tree.

But it never happened.

Three days later, Delahunty's daughter returned to the apartment to find her mother dead on the floor with a bump on her head. The family assumed she had fallen out of bed and hit her head on the doorframe, but they also noticed that her wedding and engagement rings were missing.

"I was angry," Edward Delahunty tells PEOPLE in its latest issue. "She was in good health. I wanted to know why this happened."

But now, the Delahunty family — and many more like them — are facing something even more tragic. According to police, Delahunty's death was no accident, but instead the work of one of the most prolific serial killers in Texas history. The haunting case is featured on tonight's episode of PEOPLE (the TV Show!).

Authorities have now charged former health care worker Billy Chemirmir, 47, in the deaths of Delahunty and 13 other elderly people in Dallas and Collin Counties between 2016 and 2018. Civil lawsuits name him as a suspect in at least eight more.

For more on the case of suspected serial killer Billy Chemirmir, subscribe now to PEOPLE or pick up this week’s issue, on newsstands Friday.

"Chemirmir used his healthcare experience to his advantage, targeting and exploiting seniors, some of the most vulnerable people in our community," then-Plano police chief Gregory W. Rushin said in a March 2018 press conference. "This is terribly disturbing."

Dallas County Jail

Chemirmir has pleaded not guilty, and his lawyers say that the cases against him are largely circumstantial. But authorities say that they have a mountain of evidence against him, including surveillance video, DNA evidence and even an eyewitness account of a 91-year-old woman who survived one of his alleged attacks.

Want to keep up with the latest crime coverage? Sign up for PEOPLE's free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.

A Kenyan immigrant with permanent resident status in the U.S., Chemirmir is being held in the Dallas County Jail on $11.6 million bond, pending a 2021 trial date.

For the families of his alleged victims, their grief is mixed with anger about how this could have gone on for so long. For one thing, most of the deaths were attributed to natural causes simply because the victims were elderly. "You expect someone to die at a senior living facility," says Paul Abramowitz, whose 82-year-old mother, Joyce, was found dead in 2016. "This was the perfect crime."

The Billy Chemirmir case is featured on tonight's episode of PEOPLE (the TV Show!).

PEOPLE (the TV Show!) is a half-hour daily TV show inspired by the brand's unique combination of the most popular celebrity and inspirational human-interest stories, including entertainment news, exclusive interviews, feature stories, beauty and style, true crime and more. The show airs Monday-Friday in all 12 Meredith markets, including Atlanta, Phoenix, St. Louis, Portland, Nashville, Kansas City, Hartford-New Haven, Greenville-Spartanburg, Las Vegas, Mobile-Pensacola, Flint-Saginaw and Springfield-Holyoke. The show is hosted by Kay Adams and Lawrence K. Jackson with correspondents Jeremy Parsons and Sandra Vergara. You can also stream the show daily at 7 p.m. ET/4 p.m. PT on People.com, PeopleTV app (OTT) and PEOPLE’s Facebook, Twitter and YouTube accounts.