(KRON) -- Crews responded to a fire at a San Leandro home on Monday night, the Alameda County Fire Department said. The fire happened on the 900 block of Williams Street. A single-story home is "well-involved," ACFD said. ‘Highly aggressive’ day-biting mosquitoes found in Santa Clara Other buildings are exposed to the flames. Nobody was injured, but two families were displaced. The cause of the fire is under investigation, but ACFD said it "seems suspicious." Monday's fire is the second serious fire in San Leandro in the last two days. On Sunday, a person and a dog were killed in a fire on the 14600 block of Washington Avenue.