A 24-year-old was arrested for acting suspiciously near Monarch High School on Thursday morning.

The Louisville Police Department got a call from Monarch security about a suspicious person at the school shortly before 8:15 a.m. Security reported the man was trying to get into the school and "was being evasive."

Officers arrived at the scene and were able to take the man into custody without incident.

Shortly after that, police found a backpack at the north end of the high school.

Monarch High School and Monarch K-8 were placed on lockdown while the regional bomb squad, a SWAT team and numerous deputies investigated.

Louisville Police Department Commander Jeff Fisher is unsure at this time if the backpack is related to the man taken into custody.

“Given the nature of the incident and the bag, we can’t say that it doesn’t belong to him, so as precautionary measure we seized the bag and our bomb squad is looking at it now,” Fisher said.

The lockdown was lifted shortly before 11:30 a.m., according to Boulder County Sheriff's Dispatch.

Monarch High School is located at 329 Campus Dr. in Louisville, Colorado.