MONROE — The shards of glass have been swept away and classes will resume Monday, but the frustration here continues.

The window breakage early Friday at Monroe High School is the latest in a series of incidents over the past three weeks that have disrupted school.

Bomb threats have forced the evacuation of the high school on two occasions and once at the middle school.

There also have been other non-specific threats scrawled in rest rooms, according to school and police officials.

Friday’s vandalism, in which seven glass entryway doors near the gymnasium were shot out and seven classroom windows on the south side of the school were smashed, was discovered just before 6 a.m.

With buses ready to roll within 30 minutes and officials unclear if the vandalism was related to other threats, Superintendent Larry Brown canceled classes for the entire 2,700-student district located in southern Green County.

No one entered the high school building during Friday’s vandalism spree and police are reviewing security video to look for clues.

Damage is estimated at $3,000 to $5,000 and police are following up on tips.

Police think a pellet gun, BB gun or sling shot was used to break the entryway doors, and a baseball bat may have been used on the windows.

Based on interviews with neighbors and security video, police think the vandalism may have occurred around 3 a.m., just hours after the Future Farmers of America banquet ended at the school.

“A school tends to be a vandalism target,” said Police Chief Fred Kelley. “We have no reason to believe (the incidents are) tied together but we may not know that until we get a suspect.”

A 15-year-old student recently was arrested for his alleged role in a non-specific threat found on a rest room wall of the high school.

The threat did not mention a weapon and police have recommended a disorderly conduct charge against the boy, whose punishment from the school board could include expulsion.

Kelley has applied for federal grant money for a school liaison officer at the high school, something he never seriously considered before this year.

While playgrounds, the parking lots and halls of the district’s schools were quiet Friday, sporting events, a quilt show and a concert at the high school will go on as planned this weekend with increased security.

The Abe Lincoln Spring Fling dance scheduled for Friday was canceled. The missed day of classes will be made up at the end of the year, along with two other snow days.

“It’s been a pretty tough three weeks,” Brown said. “I’m more upset that we have a few individuals in this community that think scaring our kids and parents is a joke. I don’t have the luxury of not taking this stuff seriously.”