A trans-identifying man from Pennsylvania pleaded guilty on Thursday to killing a 12-year-old girl in 2022.

Joshua Cooper, now 18 and who identifies as female and goes by Ash, admitted to killing the young girl, Morgan Connors, his “best friend,” while they were watching Netflix together.

Cooper pleaded guilty to several charges including third-degree murder, possession of an instrument of crime, and tampering with or fabricating physical evidence.

A Bucks County judge on Thursday sentenced Cooper to 15 to 40 years in jail followed by seven years of state supervised probation.

Also on Thursday, authorities revealed Cooper was adjudicated delinquent, the same as a guilty verdict in adult court, in a previous unrelated sexual assault case before the murder, the Bucks County Courier Times reported. The victim in the sexual assault case was in the courtroom on Thursday and provided a victim impact statement to the judge.

Few details around the murder have been revealed.

The deadly incident occurred on November 25, 2022 while the pair were watching Netflix in a bedroom at Cooper’s trailer park home in Bensalem Township just east of Philadelphia.

Court documents show that Cooper, then 16, said he was cleaning and organizing his father’s gun safe, and at one point Connors went to use the bathroom. Cooper somehow ended up shooting her, but Cooper’s mother ended the police interview before he could tell the rest of the story.

After the murder, Cooper allegedly called another girl via Instagram video chat claiming to have just killed someone and asking for help cleaning up and disposing of the body.

The girl told her mother that she saw blood and legs in the background of the video chat, and her mother called the police.

When police arrived, they saw Cooper running out of the back of the trailer.

Inside, officers found the body of a girl with her pants around her ankles on the bathroom floor. She died as a result of a single gunshot wound to her neck and thorax area, an autopsy found.

Cooper initially claimed he had accidentally shot the girl with his father’s hunting rifle.

A note was found in Cooper’s bedroom after the murder, but it has not been made public.

Cooper was charged as an adult, but he has been held at the Bucks County Juvenile Detention Center since his arrest.

He was originally charged as Joshua Cooper but now identifies as female, and his attorney requested that the court recognize him as Ash Cooper instead.

Paul Lang, Cooper’s attorney, referenced Cooper’s “difficult upbringing” in court and said that “taking responsibility” was a “big step in the healing process.”

Allen Gold, Connors’ grandfather and legal guardian since she was a baby, also provided a victim impact statement to the court.

“Parents should not have to bury a child. The human heart was not designed for such heartbreak,” Gold wrote, adding that the young girl was “my whole world” and had called him dad from the time she began talking.