A 16-year-old boy has been charged with murder after posing with a dead body and sending the picture to a friend via Snapchat, according to court papers.

Maxwell Marion Morton, from Jeannette, Pennsylvania, is accused of shooting his classmate Ryan Mangan, also 16, in the face. The victim's mother found her son dead in her home on Wednesday.

Police say Morton sent a selfie of himself with Mangan's body to a friend via Snapchat, a photo messaging app that allows viewers to see an image briefly before it is deleted within ten seconds.

The friend screen-shotted the image before it was erased and his mother contacted the police.

Officers say the Snapchat photo showed the victim sitting in the same position as he was found at the crime scene. It also had the name "Maxwell" across the top of the picture.

The suspect also allegedly sent text messages that said "Told you I cleaned up the shells" and "Ryan was not the last one."

Morton is being held without bail in the Westmoreland County juvenile detention centre and charged as an adult with first-degree murder, homicide and possession of a firearm by a minor, reports the Pittsburgh Tribune-Review.

County district attorney John Peck told the newspaper that it was the first time in his 30-year career as a prosecutor that he had dealt with a selfie of a suspect and murder victim.

"I've never seen it before, but it was a key piece of evidence that led investigators to the defendant," he said.

Police say Morton confessed to killing Mangan after they searched his home. A 9mm handgun hidden in Morton's basement is being checked to see if it matches the victim's wounds.

At a vigil for Mangan, a student at Jeannette High, on Thursday, he was described by his head teacher as a popular student and a "bright light".

A preliminary hearing for Morton is scheduled for 19 February.