A man charged with killing 22 women in the Dallas area of Texas over a two-year span has been found guilty of one of their deaths — his second murder conviction.

With the verdict, Billy Chemirmir, 49, automatically received a second sentence of life without parole, this time for smothering to death 87-year-old Mary Brooks.

He was already sentenced to life in prison without parole for an April conviction in the death of 81-year-old Lu Thi Harris. The local prosecutor decided not to seek the death penalty.

Chemirmir faces 11 more capital murder cases in Dallas County, but no trial dates have been set. Prosecutors in neighbouring Collin County have not yet said if they will try any of their nine capital murder cases against Chemirmir, who has maintained his innocence.

Authorities allege he preyed on women who were older and whose deaths were initially found to be from natural causes, even as family members raised alarms about missing jewellery.

Most lived in apartments at independent living communities for older people. One woman who lived in a private home was the widow of a man Chemirmir looked after while working as a carer.

Chemirmir told police that he made money by buying and selling jewellery, and that he had also worked as a caregiver and a security guard.

One woman’s survival of a March 2018 attack set Chemirmir’s arrest in motion. Mary Annis Bartel, then aged 91, told police a man forced his way into her apartment at an independent living community for pensioners, tried to smother her with a pillow and took her jewellery.

The charges against Chemirmir grew as police across the Dallas area reexamined deaths. Many of the victims’ children have said they were left perplexed by the deaths at the time, as their mothers, though older, were still healthy and active. Four indictments were added this summer.

While jurors this week were deciding Chemirmir’s guilt only in Ms Brooks’ death, they also heard evidence that led to his conviction in Ms Harris’s death as well as details related to the death of 80-year-old Martha Williams. Prosecutors for the first time presented DNA evidence linking Chemirmir to one of the deaths — Ms Williams’.

The jury also heard testimony that Chemirmir was in either in possession of jewellery and valuables belonging to the women or had offered pieces for sale and that mobile phone records put him in the vicinity of the victims.

Before Ms Bartel died in 2020, she described the attack in a taped interview that has been played at Chemirmir’s trials. She said the minute she opened her door and saw a man wearing green rubber gloves, she knew she was in “grave danger”.

Police testified they found Chemirmir the day after Ms Bartel was attacked in the parking lot of his apartment complex holding jewellery and cash, having just thrown away a large red jewellery box. Documents in the box led them to the home of Ms Harris, who was found dead in her bedroom, lipstick smeared on her pillow.

Evidence presented at trial showed that just hours before Ms Harris was found dead, Chemirmir was at the Walmart where Ms Harris was shopping.

When Ms Brooks’ grandson had found her dead in her home several weeks earlier, grocery bags from a trip to the same Walmart were sitting out on her counter. Surveillance video showed a car matching the description of Chemirmir’s pulling out just after Ms Brooks and going in the same direction.

Ann Brooks testified that as family members went through her mother’s house after her death, they found that not only was a safe missing, but most of her jewellery, including wedding rings and a coral necklace she always wore, were gone.