Firefighters responded at about 6:30 a.m. to a report of smoke coming from a garbage chute in a building at 44 McAllister St., fire spokeswoman Mindy Talmadge said.
Firefighters put out the fire in the chute and discovered a resident who had left a threatening note in their room and also took measures to deactivate smoke detectors and sprinklers in the building, Talmadge said.
An investigator heard a ticking noise in the room and decided to evacuate residents and notify the Police Department's bomb squad, which responded to do a sweep of the building, Talmadge said.
Police remained at the building to investigate the incident as of shortly before 9 a.m., she said.
The building at 44 McAllister St. is Civic Center Residence, a low-income housing complex run by the Tenderloin Neighborhood Development Corporation.