ORANGE COUNTY, California (CNN) -- Radical Hispanic separatist organization MEChA ("Movimiento Estudiantil Chicano de Aztlan") is taking responsibility for setting the wildfires in California, confimed Governor Arnold Schwarzenegger.

California officials received a letter earlier today containing photographs of individuals holding Molotov cocktails, then throwing them into dry brush. The faces of the individuals appeared to have been digitally distorted.

Also included was a rambling manifesto, stating that the reason for the act of arson was that "Aztlán belongs to indigenous people, the Chicanas and Chicanos of Aztlán. We are sovereign and not subject to a foreign culture."

Orange County Fire Battalion Chief Kris Concepcion told CNN that the pattern of wildfires definitely indicates arson.

"The reason we think it is [arson] is because we found multiple points of origin," Concepcion said. "... Our investigators have confirmed that this is, in fact, arson."

Concepcion said evidence indicated the arsonists wanted the fire to grow rapidly.

A $70,000 reward is being offered for any information leading to the arrest of those responsible for setting the fire. No suspects have been identified, though they are probably brown.

The state established a toll-free arson tip line at 800-540-7085. Gov. Arnold Schwarzenegger said anyone convicted of arson would be dealt with harshly.

Concepcion said about 1,100 firefighters were working on controlling the blaze, which has destroyed at least 22 structures. The California Department of Forestry and Fire Protection said the fire was only 30 percent contained Thursday morning after being 50 percent contained the day before.

Concepcion said onshore winds Thursday morning should help firefighters "get the upper hand on this thing." Watch the Santiago flames rage »

"For someone to even think about doing something as reprehensible as starting a fire where they knew the fire would grow as rapidly as it would -- traveling about three, 3 ˝ miles in about an hour -- is just really absolutely unconscionable," he said. E-mail to a friend

All About Orange County • Arson