Anyone with information about the arsons is encouraged to contact investigators at (877) LAPD-247, or CrimeStoppers, (800) 222-TIPS.
Psychologists say there is no single profile for serial arsonists. But given the facts of the Los Angeles case, several experts painted a portrait of the likely suspect.
He is probably between 20 and 40 years old, a loner from a broken home who feels angry about something or someone, and feels unable to communicate it in another way.
The arsonists' actions most likely had a precipitating event.
"This is a form of communication," said Dr. Jeffrey Geller, an expert on pathological fire setting at the University of Massachusetts Medical School. "Something causes him to be enraged and he doesn't know what to do with it."
"Often over the course of their life they've fused an association between angry feelings and fire," said Robert Stadolnik, a psychologist who runs FirePsych Inc., a treatment program for children and adult fire setters.
Half of all arson arrests involve juveniles, but experts say a teenager is unlikely in this case.
Why car fires? Cars can be a safe target for arsonists: easy to access, and less likely to lead to someone's injury or death. But often that impression is an illusion; fires can easily sweep out of control.
In some cases, the perpetrator defies the profile. In October, police in Maine arrested a 65-year-old woman suspected of setting at least 15 fires. The suspect was identified when a witness saw a partial license plate of her car leaving the scene of a fire. Elderly women are among the least likely to commit crimes.
"There's enough people in L.A., you're not going to find the person from a profile," Geller said.
But given that the person committing the arsons is likely out of control emotionally, some experts think he may soon make a mistake.
"I would expect that they will have this solved within the week," Stadolnik said.
Times staff writer Andrew Blankstein contributed to this report.