Officials say on March 15, Mark Laird, 18, of Boothwyn, shot and killed 15-year-old Reuben Rosado in Henry Johnson Park in Trainer, Pa.
Investigators call it a cold blooded execution.
According to police, Laird lured Rosado to the park with the promise of a gun, but instead he shot and killed him.
The next day, Trainer Borough police responded to a call in the area for a report of a deceased person.
A juvenile was later discovered in a wooded area of the park, later identified as Rosado.
Officials say a fired cartridge casing and a cell phone were both recovered from the scene.
"The cold blooded execution of a juvenile is simply incomprehensible. But, tragically, that is what happened on the night of March 15. The defendant lured his victim to the park with the promise of a gun. Instead, shot him in the back of his head," said Delaware County District Attorney Jack Stollsteimer in a statement. "Unable to keep his actions secret, the defendant then admitted to others what he had done."
Laird has been charged with criminal homicide, first degree murder, third degree murder and related firearms charges.
He is being held without bail.
His preliminary hearing is scheduled for May 5.