Update (12:52 p.m.): Police determined the bomb threat to be an "idle threat" and workers have returned to the building, according to Monrovia Police Sgt. Don Newton.
The California Highway Patrol will take over the investigation because the threat was made at a state building, Newton said. Police have a partial name of a suspect but the investigation is ongoing, he said.
Previously: Police evacuated a Huntington Drive office building Tuesday occupied by the state's Alcoholic Beverage Control (ABC) department after someone phoned in a bomb threat, a police official told Patch.
Someone called in the threat to the building at 222 Huntington Drive and police responded to the incident at 10:43 a.m., according to police. The building houses employees of ABC.
"We're clearing the building right now," Monrovia Police Lt. Zeke Cerecerez said.
Authorities blocked off Huntington Drive from Ivy Avenue to California Avenue but opened the street back up shortly before noon as a police helicopter circled above the building and firefighters filed in and out. Police could not immediately provide more information about the alleged threat.
Check back later for more on this breaking story.