Los Angeles ( CNN ) -- A joint task force Saturday was investigating a string of 35 fires across several Southern California communities , and one mayor called them a `` new form of domestic terrorism . '' Despite a $ 60,000 reward , authorities had not made an arrest by Saturday afternoon . The 21 initial fires , set in rapid succession in the Hollywood area , prompted authorities in California to post the reward in what they say is one of the worst arson sprees in recent memory . The fires were set within a span of about five hours early Friday morning , and in nearly every case they were started on parked cars , officials said . Some of the fires spread to nearby buildings . Among the homes damaged was one that was once occupied by Doors frontman Jim Morrison . The street where the house sits -- Rothdell Trail -- was the inspiration for the Doors song , `` Love Street . '' Seventeen fires were set in Hollywood ; four others in West Hollywood -- all of them within a 2-square mile area . The fire department 's Capt . Jaime Moore told CNN Saturday an additional 14 fires were reported . Investigators will determine whether they are arson and related to the other fires . `` This area of concern involves vehicle fires and fires involving vehicles in structures , '' the Los Angeles Fire Department said in a statement . `` Ten of these fires were located in the North Hollywood ( Burbank ) area and the last three were located in the Fairfax district ( southwest of Hollywood ) . The Los Angeles County Fire Department has reported one fire meeting this criteria in the Lennox area . '' West Hollywood Mayor John J. Duran told CNN the arsonists `` are using cars as an incendiary device to set buildings on fire . '' Many of the buildings are close to each other and house senior citizens who are not mobile , he said . `` We have a full-force deployment out tonight , '' Duran said . `` When you have millions of people living with millions of cars in these very dense neighborhoods , this is becoming a new form of domestic terrorism that really has got our community in a very bad spot . '' County Supervisor Zev Yaroslavsky told reporters Friday afternoon that authorities are `` dead serious about trying to apprehend the individual or individuals who are responsible '' for the arson fires . `` We want to get these SOBs before they hurt somebody , '' he said . Fire officials said they were relieved no one was hurt , although a firefighter suffered a non-life-threatening injury . `` If you 're setting something alight when people are going to bed , you obviously do n't expect them to wake up , '' resident Mark Todd told CNN affiliate KTLA . `` It sort of goes past arson to attempted murder . '' The Hollywood area is home to about 20,000 people per square mile , said Los Angeles fire spokesman Erik Scott . He also said the fires caused $ 350,000 in property damage -- a `` conservative estimate . '' Authorities deployed extra police officers after sundown . The Los Angeles Fire Department 's arson unit called in additional investigators to review surveillance footage and pore through the ashes . `` While our police officers and our fire departments are working on high alert in coming days , everyone must remain vigilant , '' said Los Angeles Mayor Antonio Villaraigosa . CNN 's Adam Shivers contributed to this report .
NEW : Arson a form of `` domestic terrorism , '' West Hollywood mayor says . Officials : The fires were started within a 2-square mile area within a 5-hour span . County supervisor : `` We want to get these SOBs before they hurt somebody '' Official : The fires cause more than $ 350,000 in property damage .