After years of control and abuse, a Chester County man killed the mothers of his two children, DA says

For years, prosecutors say, Mamadou Kallie abused and threatened two women: his high school girlfriend and mother of his child, and a new — and pregnant — paramour, whom he’d pressured to abort their unborn son.

And in the end, the Coatesville resident’s attempts to control Tiara Rodriguez-Diaz, 20, and Kimberly Ortiz-Zayas, 21, ended in tragedy on May 29, 2022. Kallie chased down the two women and executed them after they “confronted him about his misdeeds,” according to court filings.

Prosecutors described the women’s decision to meet Kallie that day as “a tragic final act of bravery and defiance.”

Kallie’s trial for murder and related crimes is scheduled to start Monday in West Chester. Jury selection began Friday, with a last-minute announcement from Chester County District Attorney Chris de Barrena-Sarobe that his office will not be seeking the death penalty against Kallie, 26, as originally intended.

The top prosecutor said the decision was made with the blessing of the victims’ families in an attempt to avoid delaying the trial — Kallie’s attorney, Daniel Miller, said he would need as long as two years to investigate Kallie’s childhood in Africa in order to properly defend him during the death-penalty phase of the trial.

Miller did not return a request for comment Friday.

In motions filed ahead of Monday’s trial, First Assistant District Attorney Erin O’Brien detailed a toxic pattern of “threats and acts of violence” Kallie used to control the women. She told the judge she intends to present evidence that Kallie had attacked both women during domestic arguments and threatened to kill their families.

“Denying the admission of evidence of the defendant’s prior assaultive or threatening behavior toward the victims would allow the defendant to successfully control and manipulate evidence at trial, as he controlled and manipulated the victims,” O’Brien said.

On the night of the killings, Kallie and Rodriguez-Diaz met at a cookout at a friend’s home in Coatesville, police said. She brought along their 22-month-old son. There, the couple got into an argument about Kallie’s relationship with Ortiz-Zayas, a disagreement that became so heated, concerned neighbors called police.

Responding officers separated the two and helped Rodriguez-Diaz secure her son in her car and leave safely.

About a half hour later, officers from nearby Valley Township were notified of a shooting on Glencrest Road, authorities said.

When they arrived, they found Rodriguez-Diaz shot multiple times in her car, and rushed her to Paoli Hospital, where she was later pronounced dead. Ortiz-Zayas was found nearby and pronounced dead at the scene. Rodriguez-Diaz’s son was in the backseat of the vehicle, unharmed.

Through investigation, the officers learned that, after leaving the cookout, Rodrigurez-Diaz contacted Ortiz-Zayas, and the two agreed to meet, according to court filings. Somehow, Kallie learned where they were, and chased after them, deliberately crashing his car into the back of Rodriguez-Diaz’s. He shot her in the vehicle, and then killed Ortiz-Zayas as she attempted to flee, police said.

At the time, Ortiz-Zayas was five months pregnant with Kallie’s son.

Ortiz-Zayas’ family said her loss, and that of her unborn son, has left them with a “rush of love” amid their grief.

“Even though Kimberly is gone, the warmth from her love continues to glow in the lives she touched,” they wrote in a remembrance of her posted online.

Rodriquez-Diaz’s family said in her obituary that she relocated from her native Salinas, Puerto Rico, to Coatesville when she was 6. They described her as a loving, caring mother and outgoing person, someone who was “always offering a big hug and a beautiful smile.”

Prosecutors wrote in court filings that Kallie met Rodriguez-Diaz in high school, a relationship that her family urged her to end. They later told police that Kallie once came to their home in 2018, armed with a gun, and demanded Rodriguez-Diaz leave with him.

Rodriguez-Diaz applied for and received a temporary protection of abuse order against Kallie in 2022, after she ended their relationship. Kallie had been stalking her and threatened her with a gun, demanding she remove his name from their son’s birth certificate, prosecutors said.

A county judge later dismissed the order when Rodriguez-Diaz failed to appear for court hearings.

Prosecutors say Kallie also abused Ortiz-Diaz, whom he had met a few years before he killed her.

He was convicted of simple assault and terroristic threats in 2019 after beating her at her home in Coatesville and destroying her cell phone. He was still on probation for this crime at the time of the slayings.

In a similar incident in 2021, Ortiz-Zayas told police Kallie visited her house late one night after she broke up with him, knocked on her window, and demanded to be let inside. He threatened to “shoot up the place” if she did not let him in, she said. When she did, she said, he beat her with a belt and a gun, and took her phone so she could not call police.

Afterward, Kallie pressured her to drop the assault charges against him, she later told police. The case was dismissed when Ortiz-Zayas did not appear for the preliminary hearing.