PORTLAND — A Lewiston man pleaded guilty Tuesday in federal court to felony gun possession after a photo of him with a gun was found during an unrelated criminal investigation.

Devon Duncan, 36, faces up to 10 years in prison on the gun possession charge.

On April 28, Meghan Duncan, 24, was shot by an armed man through the door of her Arch Avenue apartment in Lewiston. During that investigation police found a photo of Devon Duncan, her husband, holding a gun that was also found by police in Meghan Duncan’s apartment.

Duncan is prohibited from possessing firearms due to previous felony convictions, prosecutors said.

He is not considered a suspect in Meghan Duncan’s shooting.

Shortly before 1:30 a.m. on April 28, Meghan Duncan was shot five times through the door of the apartment she had shared with her estranged husband. She had responded to a knock at the front door, looked through the peephole and asked who was there, investigators said.

After she called 911, she was taken to Central Maine Medical Center in Lewiston, where she was listed in serious condition.

A Lowell, Massachusetts, man described as a violent fugitive was arrested in late April and questioned by police in connection with the Lewiston shooting.

Devon Duncan told investigators he believed the shooter had been a “drug associate” of his, according to an affidavit filed by a special agent with the Maine Drug Enforcement Agency.

Meanwhile, police in Maine secured a search warrant for the apartment and Meghan Duncan’s cellphone.

As a result of the investigation into the shooting, police recovered a brown Glock 19X 9 mm handgun between the bed and a nightstand in the apartment, according to Assistant U.S. Attorney Noah Falk.

From her cellphone, investigators recovered photos of Devon Duncan, shown in the apartment four days earlier handling the gun.

In one image, he is seen holding the gun in his right hand and “pointing it directly at the camera,” Falk wrote in court papers.

Because Devon Duncan had been convicted of two felonies, including one for unlawful trafficking in cocaine and one for fentanyl, he was barred from having a firearm.

“Duncan knew it was illegal for him to possess a firearm,” Falk wrote in court papers.

And because the gun was manufactured outside Maine, the crime was prosecuted in federal court, Falk wrote.

U.S. District Court Judge Nancy Torresen accepted Duncan’s guilty plea Tuesday, after quizzing him about his level of education, medications he was taking and whether he was admitting to the crime because he was “actually” guilty.

Falk said he had not offered Duncan an agreement on sentencing in exchange for his plea.

Duncan also agreed Tuesday to forfeit ownership of the handgun recovered in the investigation.

A sentencing date will be set after an investigation into Duncan’s background and criminal history is complete, Torresen said.