Although the suspect was considered the most likely person to have set all the blazes, a second suspect was still being detained by authorities and interrogated in connection with them on Monday.
For the victims of the arsonist, nothing can justify what he did to them, and many are searching for answers. Carole Shandler's car was among those burned.
"It feels like an act of terrorism. That we're being targeted to have spread fear throughout a community and in people's hearts. I just want to know what the reason is," Shandler said.
The Associated Press and ABC News' Kevin Dolak, Colleen Curry, Kirit Radia and Ben Forer contributed to this report.