A former Scarborough town councilor is in federal custody after holding up a Biddeford bank with a pellet gun, federal officials say.

Robert E. Patch, 46, of Dunstan Avenue, made his initial appearance Friday in U.S. Federal District Court in Portland to hear the charges against him. Bail, if granted, will be set at a detention hearing Tuesday.

Patch is charged with one count of bank robbery, a crime punishable by up to 20 years in prison. Bank robbery is a federal crime because bank deposits are federally insured.

According to an affidavit by FBI Special Agent James Lechner, Patch walked into the Maine Bank and Trust building at 28 Adams Street at about 10:45 a.m. April 9 and demanded money from a teller at gunpoint.

Lechner added that Patch told authorities he had “decided on the morning of April 9 to rob a bank.” Lechner did not say if Patch gave any explanation for his decision.

Statements from bank tellers say Patch was calm and polite, but recognizable during the robbery.

“I looked up and saw the burglar standing diagonally at my station, pointing a large black handgun at my upper chest,” a teller said in a written statement to police. “He said calmly, ‘Give me your cash.’ I stared at him and he repeated it. I took the cash on the counter and put it on top of the counter for him.”

The teller activated a silent panic alarm during the robbery, which alerted police.

The teller described the robber as about 5 feet, 10 inches in height and wearing a grey crewneck sweater and a bright teal blue neck warmer covering his nose, mouth and neck. Another teller who witnessed the robbery said the perpetrator looked like Robert Patch, a bank customer, the affidavit said.

Lechner said a third teller, who also witnessed the robbery, watched Patch leave the building and get in a teal blue pickup truck. The teller noted the truck’s license plate number, and Biddeford police alerted other law enforcement agencies of the number.

Less than 15 minutes after the robbery, Saco Cpl. Michael Maksut saw Patch’s truck northbound on Route 1.

According to Saco Deputy Chief Charles Labonte, Maksut was making a traffic stop on Route 1 when he heard the bulletin and then saw the vehicle. “He immediately jumped into his vehicle and crossed the median strip and pursued the vehicle and got behind it, but did not make any attempts to stop it,” Labonte said

Maksut immediately called for backup assistance, but when Patch turned into a gas station, Labonte said Maksut “knew he had to take action immediately to apprehend the suspect without backup.”

Maksut detained Patch at gunpoint and was securing his hands when help arrived, Labonte said. He said Patch did not resist and was not interrogated by Saco police.

According to Lechner’s affidavit, Patch had $90 in his wallet and $520 in his pants pocket. He was taken to Biddeford, where he gave a written statement expressing his decision to rob a bank.

Patch allegedly detailed the robbery and gave police permission to search his truck. In it, police say they found more than $3,400 in cash, a teal neck warmer and a pellet pistol, which Patch said belonged to his son and admitted using in the robbery.

Patch served on the Scarborough Town Council from November 2003, to November 2006.

“For the first couple of years, he was active in attending council meetings and participating in council discussions,” said Town Manager Ron Owens. “He pretty much didn’t show up for meetings during his last year on council.”

He said Patch did not offer any explanations or excuses, such as illness or family issues, for his absences.

Owens said Patch, a construction worker, took a particular interest in the construction of the new high school, but was generally “reserved and quiet.”

“He wasn’t the sort of person who would stand out in a crowd,” Owens said. He said he was very surprised to hear that Patch had allegedly been involved in a robbery.

“It’s one of those sad situations where it’s sort of hard to understand why people do certain things,” he said. “They’re people, after all. They have emotions, they make mistakes, they make poor choices, and they get in trouble when they do that.”

Although federal prosecutors sometimes delegate prosecution of bank robbers to local authorities, FBI Special Agent Gail Marcinkiewicz said federal prosecutors will retain the Patch case. She said the holdup is considered an armed robbery even though Patch only used a pellet gun.

“Although the weapon wasn’t an actual gun, it was for all intents and purposes viewed as (a weapon),” she said.