The grandmother of a teenager who brutally murdered his mother by stabbing her 46 times and then took a selfie with the aftermath has described him as an “angel.”

“Let them criticize me. I don’t care,” said Isabel Acosta, grandmother of 15-year-old Derek Rosa, who was convicted of killing his mother, Irina Garcia. In an interview with Telemundo 51, Acosta expressed her unwavering support for Rosa, saying, “You have to feel what I feel. He’s my life, he’s my grandson…he’s like another son to me. I can’t help it.”

Acosta went on to describe Rosa as “my forever angel,” despite the horrific crime he committed.

Rosa was sentenced to 25 years in prison on January 16 for the murder of his 39-year-old mother. The attack occurred while Garcia was asleep in their Hialeah, Florida, home. Fortunately, Garcia’s newborn daughter, who was in a crib next to her, was unharmed during the incident.

During his sentencing in Miami-Dade County, Rosa expressed remorse, saying, “I’m sorry.”

Initially, Rosa pleaded not guilty to first-degree murder, as reported by People magazine. However, he later accepted a plea deal, changing his plea to guilty for second-degree murder with a weapon. Following his prison sentence, Rosa will be subject to 20 years of probation.

On Oct. 12, 2023, Rosa called 911 to confess that he had killed his mother, according to an arrest affidavit obtained by Oxygen—and a recording played in court—and sent photos of her corpse to a friend over social media. 

Garcia was found dead on the bedroom floor, noted the affidavit, with multiple stab wounds to the neck. Her cause of death was due to sharp force wounds.

In a Nov. 2025 court filing viewed by Oxygen, prosecutors claimed Rosa also took a selfie depicting his bloody hand, and sent it to a friend, who told police that Rosa was “joking” and “laughing” about it. During an interview with detectives, noted the filing, Rosa admitted to cutting his mother’s neck in a place where “a lot of blood sprays out” and said he considered killing himself after the act, but decided against it.  

Rosa would not provide a motive for the killing, per the filing, however a forensic search of his phone indicated that he allegedly searched the terms, “Where is the best place to stab someone” and “Can a knife cut through bone” among other queries.   

Prosecutors argued in that filing that Rosa viewed murder as “a source of content and amusement” and had a “morbid fascination with blood, gore, and death.” 

They pointed to the timing of the murder—shortly before midnight on Thursday, Oct. 12—and to Rosa allegedly telling a friend about his Halloween costume that year: fictional serial killer Jason Voorhees from the horror franchise “Friday the 13th.”  

The defense called the Halloween theory “absurd,” in a Motion to Remand document viewed by Oxygen, adding that Rosa’s family has described him as a “sweet,” “kind-hearted” and “respectful” child, with no history of violent tendencies. 

“Your mom was a loving mother,” Rosa’s stepfather Frank Ramos told the court on Jan. 16, with the help of a translator. “Losing her destroyed our family and changed our lives forever.”