Updated 3:30 p.m. | Posted 2:50 p.m.
A Brainerd High School staffer was attacked Monday morning in the girls' locker room. She fought off the man, who fled and was later arrested by police.
The staff member is safe and sustained minor injuries, said Laine D. Larson, superintendent for the central Minnesota school district.
The incident happened before 7 a.m. in the locker room in in lower C building of north campus. "Police were called and after reviewing surveillance video and speaking to witnesses, the alleged attacker was quickly apprehended," Larson said in a statement.
"We believe this to be an isolated incident," although it has prompted the district to investigate what happened and how it can be prevented in the future, Larson said, adding that until further notice lockers rooms in all Brainerd public schools will be locked "until a staff member is available to supervise. No one should be in a locker room or fitness center alone."
The 20-year-old Brainerd man is being held in Crow Wing County jail pending charges.
Police and school officials aren't yet sure how the man got into the building, said Brainerd Police Chief Corky McQuiston. "We're looking at that to try and figure out where and how and exactly when he entered the school how long he might have been in there."
The man is known to Brainerd police, he said, adding, "I can't begin to speculate ... why he chose this person and this school on this day and time."