U.S. Sen. Susan Collins’ office in downtown Biddeford was vandalized with a vulgar message that was cleaned off Monday.

A photo posted to social media early Monday afternoon by Assistant Senate Minority Leader Matt Harrington, R-Sanford, showed the words “Trump whore” apparently spray-painted in capital red letters on the doors to Collins’ office on Main Street.

By the time a reporter stopped by the office around 2:45 p.m., the doors had been scrubbed clean.

Biddeford police Chief JoAnne Fisk said the incident is under investigation.

Collins’ office criticized the vandalism as “unacceptable” in a written statement Monday.

“Senator Collins and her staff will not be intimidated,” the senator’s chief of staff, Katie Brown, said. “Our Biddeford constituent office remains open, and we will continue serving the people of Maine.”

Harrington wrote in his post that the vandalism was “disgusting, disappointing and it’s not the Maine I grew up in. Do better.” He could not be immediately reached for additional comment.

Collins, the five-term Republican from Caribou, is running for reelection against Democratic candidate Troy Jackson.

In an emailed statement Monday, Jackson said there is “no place for this” in Maine.

“Vandalism and intimidation are wrong, full stop,” he wrote. “Senator Collins and her staff should be able to do their jobs without anyone defacing their office, and I condemn whoever did this.”

Staff Writer Abigail Driscoll contributed to this report.