Bangor High School. Credit: Gabor Degre

A threat made Friday that mentioned U.S. Sen. Susan Collins forced several schools from Machias to Bangor and Aroostook County into a “soft lockdown.” School remained in session, but no one could enter or leave the buildings without authorization.

A business in Orono received the threat Friday morning through a “vague, email message,” according to Orono High School Principal Reg Ruhlin.

Scott Porter, the superintendent of Machias schools, said the threat specified Collins and listed high schools in Bangor, Brewer, East Millinocket, Caribou, Houlton, Madawaska, Jonesport, Machias and Harrington.

School districts did not see the actual message, according to Brewer schools Superintendent Gregg Palmer.

The threat came Friday as the Republican-led Senate looked to be moving toward the acquittal of President Donald Trump on impeachment charges. Collins, a Republican up for re-election in 2020, has been one of the most-watched senators on the issue.

Collins spokeswoman Annie Clark said the senator’s office “immediately contacted the Capitol Police, who worked closely with the FBI and state and local law enforcement to quickly ensure the safety of Maine schools.”

Kristin Setera, a spokeswoman for FBI’s Boston division, said the agency was working with state and local law enforcement to identify the threat’s source. She declined further comment.

Bangor schools Superintendent Betsy Webb said Friday in a message to parents that all students were safe and that the city’s schools were taking the lockdown measure “out of an abundance of caution.”

Parents in Bangor were able to pick up their children from school, but only after showing identification and waiting outside for a staff member to escort their child out, according to a Bangor School Department alert.

In Aroostook County, schools in Fort Kent and Frenchville were also in soft lockdown. The Madawaska School department dismissed all students at 12:30 p.m. Although Houlton was on the list, the superintendent said schools were not in lockdown or going to early dismissal. Caribou High School entered a soft lockdown at approximately 11 a.m. and remained on lockdown throughout the day. School was released as usual.

After-school activities in many of the affected school districts were called off Friday, and basketball games involving high schools in Machias, Millinocket, Jonesport and Narraguagus were postponed because of the threat. Brewer High School withdrew from a swim meet against John Bapst Memorial High School in Bangor. The meet will happen Monday instead.

Authorities investigating the threat aren’t releasing its specific wording, said Stephen McCausland, spokesman for the Maine Department of Public Safety.

Around the time of another high-profile Senate vote — the vote to confirm Brett Kavanaugh to the U.S. Supreme Court in the fall of 2018 — Collins was also the subject of threats. A New York man who pleaded guilty to sending threatening voicemails to the senator was sentenced to 18 months in prison, and a Burlington, Maine, woman who was found guilty of mailing a threatening letter with white powder to Collins’ Bangor home is awaiting sentencing.

BDN writers Michael Shepherd, Bill Trotter, Morgan Mitchell, Chris Bouchard, Joseph Cyr and Jessica Potila contributed to this report.