A Centereach man admitted beating a friend to death with a baseball bat when they were both 16 years old and later burying and then digging up his victim’s remains to move them to a neighbor’s yard.

John Mann IV, now 20, pleaded guilty to a reduced charge of manslaughter in exchange for a 20-year prison sentence at a hearing before Acting Supreme Court Justice Anthony Senft in Riverhead Friday.

Mann, who had previously been charged with second-degree murder, admitted killing Henry Hernandez after he took Mann’s father’s pickup truck and damaged it.

Mann later asked Hernandez to meet him at a “sandpit” less than a mile from his house, where he waited for him with duct tape and a baseball bat, he admitted during Friday’s hearing.

“The violent end of this young victim’s life and the way his body was disposed of shows the coldhearted and brutal nature of the defendant,” Suffolk County District Attorney Ray Tierney said in a statement. “What makes this murder even more sad is that the victim Henry was only 16 years old and had his whole life before him.”

Mann’s defense attorney, Matthew Rosenblum of Commack, described his client as a “special kid who made a horrible mistake.”

“It’s a very difficult case,” he said. “We want to thank the district attorney’s office for seeing fit to prosecute this as a manslaughter and not as a murder.”

Hernandez made headlines when he was reported missing from the Timothy Hill Children’s Ranch in…