Up to 10 members of MS-13 communicated on walkie talkies as they closed in on their victim at a recreational area in Wheaton, Maryland, say officials.
The victim's "heart had been excised from his chest and thrown into the grave", according to court records.
US President Donald Trump has vowed to wipe out MS-13.
One of the suspects, 19-year-old Miguel Angel Lopez-Abrego, appeared in court on Wednesday, according to Montgomery Community Media.
He has been charged with first-degree murder and remanded in custody.