It could be another four to six weeks before the San Francisco Fire Department comes forward with the results of its investigation into the June 2 fire that killed Lt. Vincent Perez and Anthony Valerio.

Speaking outside a budget hearing Wednesday at City Hall, fire Chief Joanne Hayes-White said that while interviews have been completed, there was still another month of work left to do to find out if anything went wrong with the way firefighters battled the blaze at 133 Berkeley Way.

The National Institute for Occupational Safety and Health is also conducting an investigation but it’s not likely to be done for months, Hayes-White added.

As for the cause of the fire, it still seems like an electrical spark from an outlet appears to still be the going theory.

“All signs point to the cause being accidental,” Hayes-White said.

bbegin@sfexaminer.com