Nicholson Hall on the University of Minnesota’s East Bank was evacuated at about 11 a.m. on Friday after a bomb threat was discovered earlier in the day.

University police called the all-clear a little after noon and classes resumed as normal.

At 10:25 a.m., University police received a tip from a staff member that a handwritten threat was on the wall of a stall in the first floor men’s bathroom.

University Police first did a walk-through of the building and then evacuated the premises to search with bomb-sniffing dogs, University spokesman Steve Henneberry said.

Anoka and Hennepin county police were also there with their dogs.

University Services spokesman Tim Busse said the dogs were an extra safety precaution.

“We had enough officers on hand to do a quick visual search,” Busse said. “We decided to run the dogs through just to be sure.”

The last two bomb threats were in spring of 2011, University police Deputy Chief Chuck Miner said, and overall happen “pretty sporadically.”

“It’s not always the same procedure every time,” he said. “It depends on the circumstances.”

Ellen Day, a political science and art history junior, arrived at Nicholson for an appointment after the evacuation.

“I was surprised to see all those police cars,” Day said. “I’m glad it was just a threat.”

—Kia Farhang and Jake Stark contributed to this report.