SAN DIEGO -- The deadly Paradise fire that scorched more than 56,000 acres last fall is now considered to have been a case of arson, and investigators are targeting a handful of suspects.

FIRESTORM 2003 Firestorm Archive: Updates, Stories, Video, Slideshows Slideshows: Viewer Fire Photos Video: 10News Fire Video Archive Discuss: Share Thoughts About Fires

"We did not find a specific device. We did not find an ignition source. It's just the eliminations that we did and the most probable cause is arson," Capt. Gary Eidsmoe of the California Department of Forestry told 10News.

The fire started Oct. 26 in a remote area off Valley Center Road on the Rincon Indian Reservation, at the base of a hill known locally as Snake Mountain.

The fact there are virtually no businesses or homes in the area is one of several factors leading investigators to believe the fire was suspicious, according to 10News. It's an area where young people often hang out, residents told the San Diego Union Tribune.

Investigators have not determined how the fire started.

"We do have witnesses, but I don't want to expound any more than that," sheriff's Sgt. Darrell Carr said.

No arrests have been made, but investigators are looking at two or three suspects. A person convicted of arson may be sentenced to a minimum of 10 years behind bars and can face up to life in prison.

The Paradise fire killed two people, destroyed 221 homes and ate up about $12.6 million in firefighting costs. It was one of three Southern California fires that burned more than 376,000 acres, destroyed 2,400 homes and killed 17 people in October.

The worst of the three, the Cedar fire, began on federal land and the U.S. Attorney's Office has been silent on the investigation. Fire officials say Sergio Martinez either built a fire or fired a flare after getting lost during a weekend hunting trip, sparking the blaze.

Authorities believe the Otay Mesa fire, which scorched more than 46,000 acres, was started by a campfire set by illegal immigrants.