Police at the University of Minnesota said Tuesday that they made an arrest after authorities found a bag containing suspicious contents that led to the closure and extensive sweep of the school’s Coffman Memorial Union.

The suspect believed to be responsible for the incident was arrested Tuesday morning and is being held at the Hennepin County jail awaiting charges.

“Hats off to the UMPD for their outstanding work in identifying and locating the suspect so quickly, and for their effective and professional police response to yesterday’s events,” said a university public safety update from Pam Wheelock, university services vice president.

According to Hennepin County jail records, there was a 35-year-old man who was arrested around 3:30 a.m. Tuesday by university police for probable cause possession of an explosive device.

Workers in the building noticed the bag on the first floor of the student center and notified campus officials around 11:30 p.m. Sunday. The building houses the campus bookstore and dining area, but the union is closed on Sundays during the summer.

Authorities reviewed video of a person entering the building.

By 4:30 a.m. Monday, officials called to investigate the bag decided to close the building for a more thorough search. A school spokesman said police were bothered by what was inside the bag, but he would not give more details.

Police spent the day using bomb-sniffing dogs to search the more-than-330,000-square-foot building.