The surprise discovery of two explosive devices at the Salt Lake County Sheriff's Complex, 3365 S. 900 West, led to the evacuation of about 50 employees as Salt Lake County Fire bomb technicians dismantled them Monday.

The devices, 4 inches long, 5 inches wide and 3 inches high, had fuses and were wrapped in duct tape, Salt Lake County Sheriff's Sgt. Shane Hudson said. Detectives found them in the briefcase of a man they earlier had arrested.

This past weekend, Ryan Hesse, 28, was arrested at a West Valley hotel, Hudson said. He was wanted on a $500,000 warrant for investigation of attempted murder after driving a car Aug. 26 that sped off during a routine traffic stop. A chase ensued, and during the chase five to six gunshots were fired from the car. A passenger in the car was arrested shortly after the chase but Hesse fled on foot and remained at large.

When officers arrested Hesse on Sunday, they took the briefcase, Hudson said. During an interview with police Hesse said the briefcase contained an AK-47-type assault rifle and fireworks. Hesse was taken to Salt Lake County Jail, and the briefcase was left in a secured evidence room.

Late Monday afternoon, investigators received a search warrant on the briefcase. They opened it and discovered the explosive devices. About 5 p.m., the building was evacuated. About 25 dispatchers were evacuated and set up shop in a "mobile command center — without an interruption of communication service," Hudson said. Also evacuated were detectives and employees of a records-keeping department.

About 6:30 p.m., the device was "disrupted" by bomb technicians, and employees were allowed to re-enter the building, Hudson said.

Detectives are still investigating the explosive devices. "I don't know what they were for," Hudson said.