A Florida jury has been granted permission to view footage of a 13-year-old boy calmly confessing to the brutal stabbing of his mother over 40 times as she lay asleep beside her newborn daughter. The boy, after committing the crime, sent images of the aftermath to an online acquaintance, a judge has ruled.

Derek Rosa, now 15, is set to go on trial later this month for the 2023 slaying of his 39-year-old mother Irina Garcia at their home in Hialeah, near Miami. He is charged as an adult with first-degree murder. At issue during a pretrial hearing on Tuesday was whether prosecutors could show jurors a video of his confession to investigators.

The video, shared by local NBC affiliate WTVJ, captures Rosa recounting to detectives the chilling details of the attack. He described standing over his slumbering mother, armed with a kitchen knife, and repeatedly stabbing her in the neck, severing an artery, which resulted in significant blood loss, according to the arrest affidavit.

“She was just screaming,” Rosa recounted to the officers.

His half-sister, merely 14 days old, was sleeping nearby at the time of the incident. Following the murder, Rosa took photographs of his mother’s body and sent them to an online friend, along with another image of himself making a “hang loose” gesture, allegedly with blood on his hand, as reported by authorities.

The defense team contended that the video should be excluded as evidence, arguing that Rosa, due to his age, did not fully understand the implications of his statements to law enforcement. Additionally, Rosa had been diagnosed with autism and ADHD prior to the incident.

However, Judge Richard Hersch rejected the defense’s motion, asserting that Rosa possessed sufficient intelligence to waive his Miranda rights. Furthermore, the judge concluded that the detectives’ conduct was not coercive during the interrogation.

“I don’t find anything in the manner in which they addressed questions or presented questions which were coercive or demanding that he respond or colors this factual finding that it was a knowing and intelligent waiver of his rights,” the judge said. “And of course, the one thing that does speak volumes is that when he came to something that he did not want to talk about, [detectives] terminated the interview.”

Rosa requested an attorney as detectives began to press him about why he stabbed his mom.

As Law&Crime previously reported, Hialeah police Lt. Eddie Rodriguez noted how Rosa was “so polite” even on the 911 call after he allegedly stabbed his mother to death on Oct. 12, 2023. Everything was “Yes, ma’am; no, ma’am,” Rodriguez said.

Officers say that’s the teenager speaking to dispatch in released 911 audio.

“Miss?” Rosa said in the call.

“Yes?” the dispatcher answered.

“I took pictures and I told my friends about it,” Rosa said. “Was that bad?”

When the dispatcher asked for elaboration on who received the pictures, Rosa simply said it was his friend.

“I don’t know his real name because he’s an online friend who I play with a lot,” he said.

The murder “left everybody dumbfounded,” Rodriguez said. He called it a “huge tragedy” that left Garcia’s mother without a daughter and Rosa’s biological father essentially without a son.

The lieutenant described Rosa as an eighth grader and honor roll student at iMater Charter Middle/High School. Friends and family described him as a “good kid” and a straight-A student. The teenager had no history of mental health challenges; neither did his family. There were no fights, and he got along with both his stepfather and half-sister, Rodriguez said.

Rosa has also attracted a cadre of supporters who believe he is innocent.

“I completely believe that he is innocent of all charges,” Ariana Reyes, a Chicago mom who has been traveling to Miami-Dade County to see Rosa in court, told WTVJ and other news outlets during a press conference in January 2025.

“He is a child, he can easily be manipulated by an adult,” she said. “I believe there was more than one person in that scene, we hear noises in the background of the 911 call, I strongly believe that he’s innocent and was manipulated by someone else around that scene.”