SEARSPORT, Maine — A Bangor Savings Bank employee is accused of embezzling nearly $30,000 from customers at its Searsport branch, a bank official confirmed Monday morning.

The alleged thief was terminated after the bank did an internal investigation, said spokesman Yellow Light Breen. He did not identify the person or that person’s position at the bank.

Officials last Monday contacted the 55 customers whose accounts at the bank branch were affected to let them know.

Then on Friday the bank branch mailed a letter about the embezzlement to 2,700 other customers who bank at that branch.

“Our investigation has not shown any evidence that any of your accounts were impacted by this fraud,” the letter stated. “Nevertheless, as a valuable customer of our Searsport branch, we believe you are entitled to learn about the facts surrounding this incident.”

Breen emphasized that the bank would reimburse affected customers for “every penny” of their loss plus interest.

“We certainly felt like it would make an impression on folks if we went above and beyond, to be candid and transparent about what’s happening,” he said. “We felt that our customers would appreciate, as long as we preserved privacy and confidentiality, hearing it from us and not from the rumor mill.”

He said that officials began investigating potential fraud a few weeks ago after a customer questioned activity on his account. Ultimately, the bank discovered that an employee altered transactions that had been made at the branch.

“Unfortunately, the fraud was perpetuated in smaller amounts over an extended period of time,” Breen said.

He said that the bank contacted the Federal Bureau of Investigation for further investigation of the matter.

Greg Comcowich, a special agent and spokesman for the FBI in Boston, said Monday afternoon that the agency is aware of the allegations of bank fraud.

“We are reviewing the allegations to determine whether or not a federal crime has been committed,” he said. “Just because we receive allegations does not necessarily mean that we will conduct an investigation.”

Breen said that after the bank became aware of the potential fraud, employees reviewed all bank transactions that the alleged embezzler had handled. They were looking for any sign that the transactions had been altered.

“We always do an extremely thorough investigation before we begin reaching out to folks. We don’t want to create false insecurities on the part of our customer base,” Breen said.

But because Searsport is a small town, officials decided to send the letter to customers in order to avoid creating fodder for the rumor mill.

“We knew in a community this size, there would be lots of question marks and rumors,” Breen said. “At the end of the day, we know we’re nothing more than our reputation. We have nothing more valuable than the trust our customers put in us.”

He said that if customers haven’t been contacted by the bank about the fraud, there is no evidence that they were involved. Nevertheless, the bank’s letter warned customers that “the best protection you have against any errors or fraud is simply to review your bank statements each month and bring any inconsistencies to our attention promptly.”

Breen said Monday, “Even though we deeply regret that it’s happened, we have many internal procedures and systems that are designed to prevent fraud.”

Searsport Town Manager James Gillway said that the town had recently moved its accounts to Bangor Savings Bank, and he has been impressed by the way the bank is handling this situation.

“I have the fullest of confidence in Bangor Savings Bank’s ability to sort this situation out completely,” he said. “They were on top of it before anyone else knew about it. They reported to the officials [what] they needed to.”

He said that he believes bank managers have been acting “with integrity” about the bank fraud.

“It’s too easy to deny things. When you have a mistake, you admit it,” Gillway said.