Aiden Fucci stabbed fellow teenager Tristyn Bailey 114 times during a gruesome Mother’s Day murder in St. John’s County, Florida, according to officials.
“To say that it was horrific could arguably be made as an understatement,” state attorney RJ Larizza said at a press conference on Thursday.
At least 49 of the wounds to Ms Bailey’s hands, arms, and head were “defensive in nature,” he added.
Prosecutors announced on Thursday that Mr Fucci, 14, would be tried as an adult on an upgraded first-degree murder charge.
Thousands of community members petitioned the State Attorney’s Office and Florida governor Ron DeSantis to try Mr Fucci as an adult on the heightened charge.
Mr Fucci is accused of killing the 13-year-old cheerleader, who was found dead of “horrific” stab wounds on Mothers Day in St John’s County Florida, which sits just south of Jacksonville.
Mr Fucci was arrested shortly after the discovery of the teenager’s body, and allegedly posted an arrest selfie to snapchat from the back of a police car, which he captioned: “Hey guys has anybody seen Tristyn lately”.
The teenagers were classmates at Patriot Oaks Academy in St. Johns, but police said they are not aware of whether the pair knew one another, the Daily Beast reported.
The St. Johns County Sheriffs Department had previously announced that the teenager had died of a blunt force trauma by stabbing.
“This is a cold-blooded murder of a 13-year-old young girl who did not deserve to die,” St Johns County Sheriff Rob Hardwick told local news outlet WJXT.
“It’s a sad decision, and a sad state of affairs, but it was clear to us after we looked at what happened, that it was not only appropriate to charge the defendant as an adult, but it was really the only choice that we can make,” he said.
“The bottom line is that premeditation, could be inferred, certainly from just the sheer number of stab wounds that Tristyn Bailey had to suffer.”
Police arrested Mr Fucci on Monday, 10 May, and St. Johns County sheriff’s deputies recovered a knife near a pond where Ms Bailey’s body was found.
If convicted, the teenager could face a life sentence in prison, but would be eligible for review when he was 25 given his young age.
Ms Bailey’s family released a statement following the charging decision.
“We greatly appreciate the tremendous community outpouring from all parts of the world. Particularly for those in St. Johns that have helped from the Mother’s Day search, the vigils, remembrances and memorials,” it reads. “With the press conference sharing details of this heinous crime, the caring and love shown from the people and businesses to raise up the memory of Tristyn and the resolve of our community serve as a beacon of light in the darkness.”