A Nassau teen who police say confessed to the fatal beating of a witness in an MS-13 trial will be charged as an adult.

A judge Friday denied a request by Axel Daniel Sierra Argueta to have the case moved to family court.

Because of the suspect's age, the proceedings will continue to be heard in the youth part of the county's criminal court. The case will also be presented to a grand jury.

Investigators say Sierra Argueta took part in the beating death of 36-year-old Wilmer Maldonado Rodriguez. Police say the victim's body was found behind an abandoned house in New Cassel on Feb. 2.

According to investigators, the victim was a witness who was set to testify against MS-13. They say the suspect attacked Rodriguez three separate times, including once in October 2018 when he allegedly stabbed the victim.

Prosecutors say the suspect confessed to the crime, and admitted that he is a member of MS-13.

Prosecutors say at least three other gang members were also involved in the deadly attack, and add that those assailants stabbed Maldonado Rodriguez multiple times in the back.

Sierra Arugeta's defense attorney Dana Grossblatt says that confession may have been coerced. She is also left wondering why her client is the only person being charged.

"Based upon what he told me, I will be challenging in a motion to suppress the voluntariness of the alleged statement that he made," says Grossblatt.

She says that the confession wasn't voluntary and claims that "Miranda warnings weren't read, that he didn't understand them."

The suspect's mother walked into the courtroom Friday, flanked by two plainclothes police officers. According to a law enforcement source, that's because she is now being threatened by the gang.

Sierra Argueta is being charged with second-degree murder and he's scheduled to be back in court next week. Police say none of the other attackers have been arrested, though they are still investigating.