An arsonist hurling bottles of flaming liquid started three fires Sunday night in Santa Rosa, two at downtown churches and one at a Railroad Square civil engineering firm, Santa Rosa police and fire officials said Monday.

In quick succession starting shortly before 10 p.m., someone threw Molotov cocktails at the Church of the Incarnation on Mendocino Avenue, St. Rose Catholic Church on Tenth Street and at the offices of Carlile Macy on West Third Street.

The fires caused minor or virtually no damage, said Mark Pedroia, Santa Rosa fire's senior fire inspector.

"All three of these are connected. They are similar both in the devices and the scenario," said Pedroia. "We don't know why."

Santa Rosa police searched the area but did not locate any suspects.

"There are no indications at this time that the crimes are hate-related crimes, but that possibility is also being explored," police Sgt. Mike Tosti said in a statement.

There was no sign of damage Monday at the Episcopal Church of the Incarnation. At the Catholic church, large black scorch marks marred half of the double doors at the west entrance. A light smell of smoke hung in the air at the doors Monday afternoon.

The fires were reported almost simultaneously.

Police and fire were called to the Mendocino Avenue fire first, at about 9:45 p.m. While there, they were called to St. Rose and minutes later to the old brick building housing the civil engineering company.

At St. Rose, a priest living next door said he heard a noise, looked out and saw flames. He called for help and put out the fire.

The bottle had been thrown against the church entrance. It ignited and partially burned the outside of the wooden door, Pedroia said.

At the Third Street fire, the burning bottle was thrown against the side of the brick building. It struck and then burned itself out, causing no real damage.

You can reach Staff Writer Randi Rossmann at 521-5412 or