WHITE PLAINS, N.Y. (CBSNewYork) — A mother spoke from her broken heart to her son’s killer in a Westchester County courtroom Wednesday, as the New Rochelle man was sentenced to 10 years to life in prison.

Stivenson Desir, 20, was convicted in February of second-degree murder and criminal possession of a weapon charges in the fatal shooting of 19-year-old Iona College freshman Brandon Lawrence, Westchester County District Attorney Anthony A. Scarpino Jr. said.

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As CBS2’s Erin Logan reported, Lawrence’s mother – Sharon Lawrence – was still pleading desperately for answers as she addressed Desir.

“Why did you kill him? He never hurt you or any member of your family,” Sharon Lawrence said. “Why did you kill my son?”

“Every breath you take is a breath my son never will have because you killed him and like the coward you are, ran away and left him to die on a cold baseball field,” Sharon Lawrence continued. “I cannot begin to explain the pain I feel in my heart. It is so unbearable sometimes I feel that I want to die.”

Prosecutor Christine O’Connor mentioned that Desir told repeated lies to authorities about where he was the night of the murder.

“He has taken absolutely no responsibility,” O’Connor said.

Lawrence’s aunt also spoke in court about the unfathomable pain the family is going through and has been for 13 months.

“No amount of sentence will bring back the student; the jovial, fashionable, and ambitious young man loved by his one and only family, his church, the Iona College community, and friends,” said Denise Young.

Brandon Lawrence, of Yonkers, was found dead in the middle of a ball field at Lincoln Park in New Rochelle on April 3, 2016.

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Police said Desir pulled out a gun and shot Lawrence once in the chest while they watched two people fist fight at the park following a party at an off-campus house.

Desir had very little to say as he faced Lawrence’s family, other than, “I’m sorry.”

“I’m truly sorry for your loss, truly from the bottom of my heart,” he said.

Before sentencing Desir, Westchester Criminal Court Supervising Judge Barry E. Warhit told Desir that what he did was cold blooded and cowardly.

“I don’t know whether you fired the gun out of anger or because of some perceived slight to your fragile ego, but whatever the reason, you brought heartache and misery to the entire family,” Warhit told the defendant.

“What will your legacy be?” added Sharon Lawrence. “The boy who killed Brandon?”

Outside court, CBS2 tried to speak with Desir’s family.

“We’re sorry,” one person said when asked if they had anything to say.

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Sharon Lawrence says her son, who was just a freshman at Iona College, was looking forward to his five year-plan. He would tell his mom every day, “Mommy, I’m going places and I’m going to take care of you.”