The fire ignited after authorities threw flash grenades and tear gas into the apartment to try to flush the shooter out, Stanislaus County Sheriff Adam Christianson told reporters.

CNN: STORY HIGHLIGHTS

Yousif said police descended on the mourners and fired tear gas, flash-bang grenades and birdshot.

CNN: Fresh clashes in Bahrain as protester is buried

Afterwards, police fired tear gas and "flash bang" grenades near the main plaza, where Occupy Wall Street protesters have been camping.

BBC: US Occupy protesters clash with police at Oakland port