A Florida teen who allegedly killed his mother in her sleep was detained in an adult facility after his chilling confession was played during a pre-trial hearing.

Derek Rosa, 13, pleaded not guilty to killing his mother Irina Garcia, 39, who was found with more than 40 stab wounds in mid-October.

But during a pre-trial hearing Friday, Rosa appeared to make a chilling confession to detectives in a recording played for the court.

“I woke up, I grabbed one of the kitchen knives and I went to her room,” the recording revealed. After hesitating for a moment, he responded to a detective telling him it was OK to continue by adding, “I killed her,” the Miami Herald reported.

The teen is accused of stabbing his mother with a purple-handled knife 46 times while she slept next to her newborn baby, before sending bloody photos to a friend of his mother and his hands.

After the recording played, Miami-Dade Circuit Judge Richard Hersch ordered Rosa to be detained in an adult facility until his trial.

The student’s attorneys had argued the teen should be moved to a juvenile facility, citing that he was served breakfast between 1 and 2 a.m., didn’t have a specific class schedule, and wasn’t given his glasses without requesting the item first.

He was originally housed in a juvenile facility for two weeks after his initial arrest but was moved after being charged as an adult with first-degree murder.

Hialeah Police Detective Joseph Elosegui said Rosa had used a computer to gather information to murder his mother.

After the attack, the iMater Middle/High Charter School student confessed to the murder to 911 dispatchers and he did not put up a fight when police arrived to the scene to find his mother’s body next to her 14-day-old daughter.

He faces life in prison.