The man who killed 2-year-old Nikolette Rivera in a botched drug-related shooting in Kensington in 2019 died by suicide in state prison Sunday night, two days after he arrived, authorities said.

Tayvon Thomas, 27, was found unresponsive in his cell just after 11 p.m. by security staff at State Correctional Institution Rockview, according to a spokesperson for the state Department of Corrections.

Pennsylvania State Police are still investigating the death.

Thomas pleaded guilty to killing the child by indiscriminately shooting into a Kensington house with an AK-47. In August, he was sentenced to at least 55 years in prison. The toddler was in the arms of her mother, Joan Ortiz, when she was struck in the head. Ortiz and a carpet cleaner who was inside her house at the time were also injured.

Prosecutors say Thomas and Freddie Perez were targeting Nikolette’s father because of a drug dispute. The high-profile killing ignited public outcry among residents in the neighborhood, and it prompted outrage from city officials. Perez, who also pleaded guilty in the child’s death, is awaiting sentencing.

Thomas apologized at his sentencing hearing. As he was escorted out of the courtroom, Ortiz had the prosecutor relay a message to him: “She forgives him.”

“I didn’t want to hold any anger,” Ortiz said after the hearing. “There’s nothing that can bring my daughter back.”

Defense attorney Earl Kauffman said Thursday that Thomas’ life was troubled “from the very beginning.” He said Thomas was abused as a child, and that an uncle poured boiling water on him when he was an infant, leaving his face with massive scarring.

After the sentencing, Kauffman said, Thomas didn’t want to appeal. “He just suffered with it,” he said.

Nine inmates in the state prison system have died by suicide this year, according to a spokesperson.