Police believe the suspect, who hit Bank of America and cPort Credit Union on Friday, may also be responsible for two earlier robberies.

Police say back-to-back bank robberies in Portland on Friday, including one in which the suspect threatened a customer with a handgun, may be the work of a man they are seeking for two other bank robberies in the past three weeks.

The cPort Credit Union at 285 Forest Ave. was robbed around 11:55 a.m. Friday by a man who showed a handgun and demanded cash.

A few minutes later, at 12:20 p.m., a man matching the description of the credit union robber held up the Bank of America branch at One City Center on busy Monument Square.

Police released security camera images showing the robber pointing a handgun at a man in front of the tellers’ counter while thrusting a pink binder toward the man’s chest. Police said it is not unusual for robbers to bring something to carry money in.

“It’s a very violent and desperate act, robbing a bank in this manner,” Cmdr. Gary Rogers said during a news conference Friday afternoon. “We’re not necessarily talking about somebody who is thinking rationally.”

The robber is described as a black man in his 20s or 30s, about 6-feet, 1-inch tall with a thin build. He was wearing a black hooded sweatshirt and a tan bucket-style hat with lime green trim.

He was last seen going toward the parking garage at One City Center.

Police didn’t believe he stayed in the garage, but they locked it down as they searched the cars with a police dog in case he was hiding among the vehicles or had discarded items that might be evidence. Drivers weren’t allowed to access their vehicles and a large crowd gathered in the plaza to watch as police surrounded the garage during the search.

The garage reopened at 2 p.m. and police later released a description of a vehicle – a late-model, red Ford or Mercury sedan – that witnesses saw speeding from the area with two black men inside. Rogers wouldn’t release information on where the car was seen.

Friday’s robberies may be the work of the same man who robbed TruChoice Credit Union on May 26 and University Credit Union on May 14, Rogers said. Both of those robberies were committed by a heavily disguised black male wielding a handgun.

The man who robbed the University Credit Union at 1071 Brighton Ave. was described as a slender black man with dreadlocks tucked under a baseball hat. He appeared to be wearing a false mustache along with sunglasses, a North Face jacket with a hood, pants, sneakers, gloves and a baseball hat with white letters. He showed the handgun and demanded money.

The man who robbed the TruChoice Credit Union branch at 272 Park Ave. was described as a black male, 5 feet 10 inches to 6 feet tall, with a thin build, wearing oversized glasses, a fake mustache, and a dark Afro-style wig. He wore a white hat, dark suit, light colored shirt with a striped tie, and black shoes.

“We are starting to see a pattern in these robberies and that’s something we use in deploying our officers,” Rogers said without elaborating.

Stephanie Beattie was headed into One City Center to teach a fitness class at the Bay Club when she passed a man she believes was the Bank of America robber.

“He looked suspicious. He was jogging out of the bank,” she said. “It’s 70 degrees out and he was wearing a hooded sweatshirt and being conscious of keeping the hood on.”

Beattie passed within 3 feet of the man as he left the bank through the doors into the lobby of One City Center. She didn’t see a gun or money and couldn’t see the man’s face clearly because of the hood and the mirrored sunglasses he was wearing. His pants were so loose they looked as if they would fall down as he ran away, she said.

Joe Grant was working on an air-conditioning project in the parking lot of the Asylum night club, which backs up to the garage. He didn’t see a suspect run past, but did see an officer running down Free Street with a rifle.

Police ask that anyone with information to call 874-8575 or send an anonymous tip by texting the keyword “GOTCHA” plus the message to 274637 (CRIMES).