PORTLAND — A South Portland man has pleaded guilty to federal charges of using a police officer’s gun to rob a bank and a convenience store.

South Portland police captured Joseph Morrill, 23, shortly after the TD Bank robbery in April, after he dropped his cellphone while making his getaway on a bicycle.

Morrill pleaded guilty Monday in U.S. District Court to armed robbery and firearms charges, the U.S. Attorney’s Office announced.

Prosecutors say that on Sept. 21, 2012, a .40-caliber Glock pistol and badge belonging to a Cumberland County Sheriff’s Office detective were stolen from the officer’s private vehicle in South Portland.

Morrill used that gun on April 17 to rob a Cumberland Farms store on Cottage Road in South Portland of $182, and on April 22 to rob a TD Bank branch on Market Street in South Portland of $5,612, according to information provided as part of the guilty plea.

Police, notified by a holdup alarm, responded to the bank right after the robbery with a dog trained to track suspects. The dog followed the track to a clump of bushes behind a nearby building on Ocean Street, according to the complaint filed in federal court.

There, police found cigarette butts, tire tracks from a bicycle and a cellphone. The cell phone was registered to Morrill and police were able to compare images on the phone with mug shots from Cumberland County Jail. Morrill was indicted last year on charges of burglary and theft.

Soon after the robbery, the phone started ringing. Police surmised it was Morrill trying to locate his lost phone, the complaint said.

Police also were able to get texts that had been sent and received on the phone making reference to the gun, the robbery and to drugs, police said in the complaint.

Police located Morrill at a house at 231 Broadway and although he denied the robbery at the time, they found dark clothing and sneakers similar to what the robber was seen wearing on security video. As Morrill was being interviewed, investigators noticed he was wearing a bracelet that matched one worn by the bank robber.

Police charged Morrill June 5 and found the gun June 14 after executing a search warrant at 865 Broadway.

Morrill faces up to 30 years in prison and a $250,000 fine for robbing the convenience store, up to 25 years in prison and a $250,000 fine for robbing the bank and up to 10 years in prison for possessing the stolen gun.

The most serious potential penalty, however, is a prison sentence of seven years to life for using a stolen pistol in the bank robbery. His sentencing will take place at a future date.

The investigation was conducted by South Portland police and the FBI.

Dave Hench can be contacted at 791-6327, or at:

dhench@pressherald.com