PITTSBURGH —A 16-year-old sent a cellphone selfie that also showed another teen he had just fatally shot in the face, sitting in a chair, investigators said in court papers charging the teen.

Maxwell Morton faces a preliminary hearing Feb. 19 on charges of first-degree murder, criminal homicide and possession of a weapon by a minor following the shooting Wednesday of Ryan Mangan, who also was 16. Mangan’s funeral was Monday in Jeannette, a city of roughly 9,500 residents about 25 miles east of Pittsburgh.

Investigators zeroed in on Morton after the mother of a third boy called police a day after the shooting to report that Morton had sent her son the picture with Mangan’s lifeless body in the background.

Online court records don’t list an attorney for Morton, and a woman who answered his home telephone Monday said the family has yet to hire one, before declining to comment.

According to a criminal complaint, Morton took the photo with Snapchat, a messaging app that lets people send photos, videos and texts that disappear in a few seconds, unless the recipient saves them. If that happens, the sender is automatically notified.

In this instance, the boy who received the photo saved it, and his mother turned it over to police.

The photo “depicted the victim sitting in the chair with a gunshot wound to the face,” which, police said, is how Mangan’s mother found her son when she returned home at about 6 p.m. that day. The Snapchat photo had the name Maxwell at the top, and Morton also sent the same boy text messages saying, “Told you I cleaned up the shells” and “Ryan was not the last one,” according to the criminal complaint.

Westmoreland County District Attorney John Peck would not comment on the messages, including whether authorities believe Morton was referencing plans to kill others. Peck, a county prosecutor for 31 years and the district attorney since 1994, said it was the first case he had seen “where the suspect photographed the crime scene.”