Lowell police are in the midst of an investigation and they want to know: Do you recognize this individual? But it’s not for the usual reason.

Police have turned to the public for help after a painting of a male officer from the city, dating back to 1964, was discovered in the studio of a well-known photographer who died in April. Police hope to figure out who the man featured in the artwork is, and return the portrait to his family.

“It’s a mystery,’’ said Captain Tim Crowley. “But somebody deserves to get it. We just don’t want to let it sit there and collect dust.’’

Crowley said the department was given the framed painting last month by Jason Nobrega, the grandson of photographer George Poirier. Nobrega had found it as he cleared out Poirier’s studio on University Avenue.

The image shows a man with white hair and glasses, wearing a white-and-blue hat. Two rows of bronze-colored buttons dot the front of his uniform, which also bears a police badge.

Police are guessing that the uniform is that of a high-ranking officer during the 1920s or 1930s, and that the man was a lieutenant, but they have been unable to glean much other information about him from the painting.

An envelope containing a receipt that read “1964,’’ indicating when the painting had been paid for but likely never picked up, has been the department’s best lead. A black-and-white photograph of the man in the painting was tucked inside the envelope.

Sergeant Marisol Nobrega, who happens to be Jason’s wife, was tasked with bringing the portrait to the department after her husband discovered it.

“It was paid for in full — $125 — which, in 1964, that was a lot of money,’’ she said. “They gave it to me, and I was just hoping to get it back to maybe a family member.’’

She said it was unclear if the photograph found in the envelope was taken by Poirier.

To help with their investigation, police posted a picture of the painting to Facebook and Twitter last Tuesday. So far, their efforts have been fruitless.

“We had a couple of guesses,’’ said Crowley. “But nothing has panned out.’’

Crowley plans to hand the photograph, receipt, and painting over to the city’s historical society to see if employees there can come up with any additional clues to help close the case.

“We would like to find out who it is, and then track down the family, and get it to them,’’ he said. “We are going to keep pushing it out [on social media] now and then, but I am hoping the historical people can come up with something.’’

Steve Annear can be reached at steve.annear@globe.com. Follow him on Twitter @steveannear.