MADISON, Wis. (CBS 58) -- Police in Madison have found no evidence of explosives after investigating two bomb threats against 7-Eleven stores in the city Thursday, Jan. 28.

The threats came in at 11:50 a.m. and 12:50 p.m.

Police say in the first incident, a caller dialed 911 and stated that they'd placed explosive devices at the 7-Eleven near Lake and State Street and could detonate them at any time.

A similar call was placed about an hour later, referencing the 7-Eleven near Park and Buick Street.

UW-Madison police evacuated Memorial Library and the nearby extension building. 

After a thorough search of both buildings, no suspicious items were found. The scene was cleared shortly before 3 p.m. 

Detectives are working to identify the caller.