VASSALBORO — A five-month federal investigation into allegations of mail fraud at the East Vassalboro post office has been finished, but no decision has yet been made about whether criminal charges will be filed in the case.

Reports that donations to the Vassalboro Library and the Vassalboro Historical Society might have been diverted illegally surfaced in April, prompting enforcement officers within the Office of the Inspector General of the U.S. Postal Service to open an investigation.

At least one check that was mailed to the library never reached its destination, library officials said, which prompted the Vassalboro Historical Society to warn donors that their mailed checks may not have reached their destination.

The suspect’s identity has not been released, but London Mulcahy, a spokeswoman for the inspector general’s office, said the investigation focused on one person.

Previously, Thomas Rizzo, a U.S. Postal Service spokesman, said a Vassalboro branch employee did leave the postal service in April, but declined to comment further.

According to Mulcahy, the federal investigation was closed in September and sent along to the U.S. Attorney’s Office for review and possible criminal charges.

“We have submitted the paperwork to the U.S. Attorney’s Office and we’re waiting for a decision,” she said.

Assistant U.S. Attorney Donald Clark would not comment on the case’s status, and said he could not confirm that the case was with his office.

He said the office typically would not comment on any investigation unless and until it has led to the filing of criminal charges.

Matt Hongoltz-Hetling — 861-9287 mhhetling@centralmaine.com Twitter: @hh_matt