A just-engaged couple have been charged with murdering a 54-year-old Rhode Island woman, pumping 9mm bullets into her chest with what appears to be a 3D-printed gun, police said.

A photo of the suspects in bed, posted shortly after the shooting, bore the caption: “We some fighters and some shooters.”

Pawtucket police said they were called to the home of Cheryl Smith on New Year’s Day and found her dead of multiple gunshot wounds.

They then arrested Shaylyn Moran, 18, who used to date Smith’s son, and her new boyfriend, Jack Doherty, 23, of Albany, at a Hampton Inn. Both were arraigned Thursday on first-degree murder and conspiracy charges and held without bail.

Detective Sgt. Christopher LeFort of the Pawtucket Major Crimes Square said investigators are still examining the murder weapon, “but it does appear to be 3D-printed.”

“It’s the first one I’ve seen used,” LeFort said.

The first successful firing of a plastic 3D-printed gun was in 2013 and was followed by warnings from law enforcement and bans on the technology in some locations.

LeFort said it was not clear where the couple obtained the weapon. He said it appeared similar to a gun Doherty was holding in a selfie posted to Facebook on New Year’s Eve.

“Omg u better lemme hold it when I get there,” Moran replied to the photo from a Facebook account under an alias, the Providence Journal reported.

In the ensuing hours, they each announced their engagement on their Facebook pages. Then, police said, they left the Hampton Inn and went to Smith’s home.