Fire officials are investigating what caused a Sunday morning blaze that temporarily shut down a stretch of South Bere­ta­nia Street.

The fire was reported shortly before 8 a.m. and damaged about half of a vacant restaurant — the former Bella Mia Pizzeria — at 2222 S. Bere­ta­nia St., according to Hono­lulu Fire Department Battalion Chief Geoff Chang.

A fire investigator at the scene Sunday afternoon said the building had been boarded up but that homeless people obviously had been living inside.

There was heavy smoke coming from the right side of the building, said HFD spokes­man David Jenkins.

The fire was under control at 8:10 a.m.

The single-story building used to be a restaurant before it closed down, and fire crews received reports that at least one homeless person was possibly living there, Chang said.

Crews found nobody inside, and nobody was hurt in the fire, he added. The total damage caused by the incident is yet to be determined

The structure’s interior is a total loss, Jenkins said.

Police closed Beretania between Isenberg and McCully streets so fire crews could respond, but the roadway was reopened to vehicle traffic at about 9 a.m.