The 50-year-old was found dead in his cell, and Texas Department of Criminal Justice spokeswoman Hannah Haney reported his unnamed cellmate was identified as the "assailant." Chemirmir's cause of death was not released.
The murder happened after prosecutors in two Texas counties decided not to seek the death penalty for Chemirmir's crimes. The former health care worker was accused of going on a murdering spree in Dallas and Collin Counties between 2016 and 2018, according to The Dallas Morning News.
Chemirmir killed his victims by smothering them either inside their homes or at senior centers and then stole their jewelry to sell for a profit. Police opened an investigation on him in 2018 when 91-year-old Mary Bartel told police Chemirmir broke into her home and smothered her with a pillow.
Police found Chemirmir the next day in the parking lot where he was living with jewelry and cash in hand while throwing out a large red jewelry box. The box's contents brought police to the home of 81-year-old Lu Thi Harris, who was found dead in her bedroom earlier that day.
"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."
In April 2022, Chemirmir was found guilty and convicted of capital murder in the death of Harris, according to NBC News, and later found guilty of killing 87-year-old Mary Brooks. He was sentenced to two consecutive life sentences without the possibility of parole.
Chemirmir maintained his innocence by telling The Dallas Morning News last year, "I am not a killer. I'm not at all what they're saying I am. I am a very innocent person. I was not brought [up] that way. I was brought [up] in a good family. I didn't have any problems all my life."