It took multiple local law enforcement agencies to connect a series of unsuspecting deaths to one of the most prolific serial killers in Texas history.

Season 2, Episode 4 of Prosecuting Evil with Kelly Siegler examines the crimes of Billy Chemirmir, a Kenyan killer accused of primarily smothering nearly two dozen elderly women in several Dallas-area retirement communities. The vulnerable victims, most of whom had jewelry missing from their person and homes, were initially believed to have died of natural causes.

That changed in December 2017.  

“The question becomes, how many murders did he commit, and where all is he committing these murders?”  wondered Siegler.

The 2017 death of Carolyn MacPhee

On December 31, 2017, elderly woman Carolyn MacPhee uncharacteristically failed to arrive at a watch party to see the NFL’s Dallas Cowboys play, according to her sons, Robert and Scott MacPhee. When she didn’t attend church, and calls went unanswered, Scott MacPhee said, “It was very obvious there was something wrong.”

The sons’ fears came true when they found “the sweet, sweet lady” dead on the bedroom floor of her Plano residence, about 20 miles north of Dallas.

First responders and law enforcement members found no signs of a struggle, deeming MacPhee died of old age. However, the horrified sons noticed their mother’s jewelry, including her wedding ring, was not with her body.  

Authorities guessed it wasn’t uncommon for elderly persons to hide their valuables.

Police are called to an area attack on Mary Bartel

Less than three months after MacPhee’s seemingly unremarkable death, on March 19, 2018, Plano police responded to reports from a retirement community, where personnel were unable to wake 90-year-old Mary Bartel. Responders rushed Bartel to an area hospital, and when she woke, she described a harrowing ordeal.

“Around 8:30 in the morning, she walks to her front door after hearing constant knocking,” Detective Paul Martinez told Prosecuting Evil. “As she was going to the door, the suspect pushes his way in.”

Bartel stated she complied with the intruder’s demands to get on the bed before he smothered her with a pillow and rendered her unconscious.

Like MacPhee, her wedding band and other rings were missing from her fingers.     

When investigators visited Bartel’s residence, they learned her neighbor across the hall, Ann Conklin, had died just one day earlier, furthering suspicions.

Police canvassed Preston Place and learned through management that one resident’s son had recently reported a suspicious male sitting in his Nissan Altima for an extended period at the senior living community. The son approached the driver, and the driver claimed he was waiting for a therapy session, but the circumstance left the son uneasy enough that he wrote down the license plate number. 

The registration led to Billy Chemirmir.

A look into Kenyan man Billy Chemirmir

Chemirmir was a Kenyan man who came to the United States in the early 2000s. In June 2016, he was arrested for criminal trespassing after allegedly posing as a healthcare worker at a retirement facility in Dallas, a place Martinez said the suspect had no affiliation.

As the investigation into the attacks on MacPhee, Bartel, and Conklin continued, Chemirmir was wanted by authorities for a separate public intoxication charge. One day after Bartel’s attack, police set up a surveillance post to watch Chemirmir and witnessed him discarding a red jewelry box in a dumpster at his apartment complex.

A closer look at the jewelry box showed it belonged to 81-year-old woman Lu Thi Harris, and in Chemirmir’s possession were Harris’s bracelets, house keys, and cash. They swiftly took Chemirmir into custody — then for the outstanding warrant — as detectives went to pay Harris a visit at her Dallas-Plano-area home.

When they arrived, Dallas detectives were already there to response to Harris’s death, stating their initial assessment that Harris died of natural causes. Plano investigators, with Chemirmir in their custody, requested authorities look again.

“They went back inside and found smeared lipstick on Lu Thi Harris’s pillow,” according to Martinez, indicating the victim — like Bartel — had been smothered. 

A homicide investigation was now underway.

A receipt found in Harris’s home led detectives to a local Walmart, where Chemirmir was captured on surveillance video allegedly stalking the victim down the aisles on the day of Harris’ murder, as seen on video published by Prosecuting Evil. 

Martinez said Chemirmir was “happy” and without concern while detained, even when the line of questioning shifted from the outstanding warrant to Harris and the others, as seen in the video-recorded interview. Chemirmir appeared eager to help the police and allowed them to take his cell phone — a move that would later help connect him to his purported victims.

Chemirmir denied any involvement in the women’s deaths but was charged with the capital murder of Lu Thi Harris and the attempted murder of Mary Bartel.

Police uncover the murder of Mary Brooks

Detectives continued to look at more senior citizens’ deaths that might have been inaccurately categorized as natural passings and soon discovered the January 31, 2018 death of 87-year-old Mary Brooks — a death that occurred in nearby Richardson, Texas, after MacPhee’s death and before Conklin’s.

Brooks was found dead after her grandson performed a wellness check and, like the others, was believed to have died of natural causes.

As seen in bodycam footage of the death scene, responders found bags of new groceries and a receipt proving Brooks was at Walmart shortly before her death. Not only was it the same Walmart where Chemirmir was captured allegedly stalking Harris, but cameras placed the suspect there at the same time as Brooks.

“When Mary Brooks was there, Richardson P.D. was able to show in the video Billy Chemirmir was parked in relation to where Mary Brooks was parked,” Martinez told Prosecuting Evil. “When Mary Brooks returned to her car, you see the silver Nissan Altima, which is believed to be Billy Chemirmir’s vehicle, exit with her and follow behind her, and shortly after was when she was found deceased.”

Law enforcement agencies in Plano, Dallas, Richardson, and elsewhere, started a task force.

The case against Billy Chemirmir

Shannon Dion, whose 92-year-old mother, Doris Gleason, was presumed to have died of natural causes in 2016, said she was “floored” when contacted by the task force in 2018. Investigators then looked into the possibility that Gleason, and others, were connected to Chemirmir.

Loved ones confirming that jewelry found in Chemirmir’s possession belonged to their deceased relatives, plus the data extracted from Chemirmir’s phone, helped the death toll climb to a staggering 22 murder victims and two attempted murder victims.

“This makes Billy Chemirmir one of the most horrendous, prolific serial murderers in Texas history,” Siegler said.

Lead prosecutor Glen Fitzmartin of the Dallas County District Attorney’s Office told Prosecuting Evil that the state’s best shot at convicting Chemirmir was to tie him to a single, strong case, which they believed belonged to Lu Thi Harris.

“Having Mama’s case not being tried was incredibly frustrating, but I also recognize the need for the strongest case,” said Dion. “The goal was to get those convictions, and if that wasn’t my ma’s case, then O.K.”

Jury selection began on November 12, 2021, three years after Harris’ death, and the fast-approaching COVID-19 pandemic would severely hinder courtroom protocol. Siegler especially grew concerned that jurors wouldn’t get “the real feel of anybody’s pain or anguish or frustration” since parties weren’t allowed inside the courtroom and had to view the proceedings on C.C.T.V.

The case of Harris’ homicide was one of circumstance, and Chemirmir claimed he purchased Harris’ jewelry from a seller and continued to deny having a role in her death. Prosecutors, however, relied on GPS and cell phone data that placed him at locations of interest relative to his alleged victims.

“What [the prosecution’s] expert is able to say is that the device they believed belonged to Billy Chemirmir was pinged or located in certain areas, but they cannot say that it was actually Billy himself,” defense attorney Kobby Warren told Prosecuting Evil. “It’s simply the device.”

Prosecutors also relied on the powerful August 2, 2018, deposition of survivor Mary Bartel — who’d died in 2020 before the trial, according to The Associated Press.

“I heard this very insistent rapping at the door,” Bartel said in her video-recorded deposition. “The door was opening inward, and my eyes were just fixated on these green, rubber gloves … I knew instantly, number one, I should not have opened the door. Number two, my life was in grave danger.”

The defense team, which included Warren and two others, argued Bartel couldn’t identify her attacker’s face, nor did she mention an accent (like the thick one Chemirmir had) when the assailant told her to get on the bed.

Ultimately, the jury found themselves deadlocked 11 to one, and a mistrial was declared.

Billy Chemirmir’s second murder trial

Dallas County Criminal District Attorney John Creuzot joined Fitzmartin in a second attempt to convict Chemirmir of Harris’ murder, beginning on April 12, 2022, after COVID-19 restrictions lifted. Unlike the first trial, it did not include the jury seeing Chemirmir’s police interview, which showed a relaxed and willing-to-help version of Chemirmir claiming he purchased Harris’ jewelry from a third party.

“When they didn’t play the interview at the arrest, that was a game-changer because, that way, he wasn’t able to spew his lies without any cross-examination,” Dion said.

Still, the defense questioned if the state could prove its case beyond a reasonable doubt, pointing out that all the evidence against Chemirmir was merely circumstantial.

Ultimately, the jury found Chemirmir guilty of capital murder, and he was sentenced to life without the possibility of parole.

“I have goosebumps when the jury renders the conviction that he is guilty,” Dion recalled of the verdict. “There is such a flood of relief.”

Since Chemirmir’s conviction, Dion, the MacPhee sons and more of the victims’ children united to create the nonprofit foundation Secure Our Seniors’ Safety (S.O.S.S.), aiming to highlight the vulnerabilities of those in senior communities and ensure their safety.

“When I worked through that Mama was the eighth victim in three and a half months, and that this had happened at three other well-respected properties in the metroplex, that’s when I knew that something had to change,” Dion told Prosecuting Evil.

On October 7, 2022, Billy Chemirmir was tried and convicted for the homicide of Mary Brooks. One year later, he was murdered behind bars.

Don’t miss all-new episodes of Prosecuting Evil with Kelly Siegler, airing Saturdays at 8/7c on Oxygen.