Last Updated 4:01 p.m. ET
LOS ANGELES Detectives in Los Angeles spent early Sunday analyzing security video camera footage and following up on other leads after a half dozen more vehicles were set on fire on New Year's Eve, the latest rash of suspicious car fires in the city.
The outbreak of arson fires has left a trail of smoldering debris in Hollywood, West Hollywood, North Hollywood and the Fairfax district of Los Angeles since Thursday.
Authorities said they were investigating a total of 39 suspicious fires. Most of those fires were set in parked cars. In several cases, flames have jumped to carports and apartment units.
"They are working on hundreds of clues, interviewing dozens of witnesses, picking up countless pieces of evidence," police Cmdr. Andrew Smith said of the detectives.
Authorities haven't said how the car fires were sparked or what was collected at the crime scenes. They were unsure if the rash of fires were the work of one arsonist or multiple people or copycats.
There have been no injuries.
Extra patrols were out in force on New Year's Eve. One of Saturday's attacks occurred at the Hollywood and Highland entertainment complex, a popular tourist destination and hotspot for holiday revelers. Firefighters responded to a report of a small car fire in a parking structure that was out by the time they arrived.
Firefighters routinely are called to put out burning cars, but this recent spate has been unusual because of the frequency and location of the fires. Crews have been responding to other emergencies despite the focus on solving the fire arsons, fire spokesman Erik Scott said.
Police urged residents to check their cars for any signs of tampering and take simple precautions such as locking their cars, keeping the garage lights on at night and reporting suspicious activity.
"We are not going to rest," Los Angeles Fire Department assistant chief Pat Butler said Sunday at a joint police-fire news conference. "We are going to work tirelessly."