Investigators are looking into the cause of at least six structure fires over a 24-hour period in Minneapolis, including at a vacant house that went up in flames twice.

The most damaging fire happened about 12:20 a.m. Tuesday when crews arrived in an alley on the 3700 block of 19th Avenue S. and found two detached garages fully engulfed in flames. Residents in two homes were evacuated as a precaution, but firefighters extinguished the blaze before fire reached then, said Minneapolis Assistant Chief of Administration Melanie Rucker.

Both garages were destroyed and two nearby homes were damaged by the fire and heat, she said.

The first fire broke out at a church about 4:30 a.m. Monday on the 1000 block of S. 8th Street. The fire was contained to outside of the building.

About two hours later, crews responded to a fire at a boarded up house on the 1200 block of N. Knox Avenue, an address where there have been several other fires, Rucker said. The fire was confined to a rear porch. Crews returned to the 2½-story home at 11:26 p.m. Monday on a report that somebody started a fire. The blaze caused minimal damage to the back door frame, Rucker said.

Crews also extinguished a garage fire in the 2500 block of NE. Polk Avenue just before 11 p.m. Monday. They also put out a fire outside a grain elevator on the 3700 block of Dight Avenue shortly after 1 a.m. Tuesday.

Nobody was hurt in any of the fires, Rucker said.

Tim Harlow • 612-673-7768