ORANGE COUNTY , California ( CNN ) -- One of the larger fires in Southern California was deliberately started by someone with apparent knowledge of arson , a fire official said Thursday . Firefighter Luke Perisin sets a backfire Wednesday against the Santiago Fire in Live Oak Canyon , California . The Santiago Fire in Orange County was started in two places along a little-traveled road , according to Chief Chip Prather of the county 's fire authority . The fire , which has burned more than 25,000 acres , was started in brush just off Santiago Canyon Road , not close to homes . It spread rapidly , indicating the arsonist had some knowledge of winds and other factors . `` It is a confirmed arson . There was evidence found at the scene . That is the purpose of our early declaration of it being an arson-caused fire , '' Prather said . He would not describe the evidence . Watch how the evidence points to arson » . Prather said officials originally thought the fire had three points of origin instead of two . The Santiago Fire 's points of origin are considered crime scenes , said Jim Amornino , a spokesman for the Orange County Sheriff 's Department . The reward for information leading to an arrest has increased to $ 250,000 -- $ 50,000 each from the governor 's office , the U.S. agency of Alcohol , Tobacco , Firearms and Explosives , and the FBI , Prather said . KFI radio has chipped in another $ 100,000 , the sheriff 's department said . 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 . If a suspect is to be found , `` it 's going to be by a clue from the public , '' said county Sheriff Mike Corona . About 1,100 firefighters were working on controlling the Santiago Fire , which has destroyed at least 22 structures , according to Orange County Fire Battalion Chief Kris Concepcion . 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 . Watch the Santiago flames rage » . The motive of the Santiago Fire 's arsonist was a mystery to Concepcion . `` That 's the part that I really ca n't figure out , to tell you the truth , '' he told CNN . `` That individual knew on Sunday when this fire started that we had , really , the perfect storm , if you will . We had the heavy Santa Ana winds , we had the low relative humidities , we had the high temperatures . `` And then 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 , 3½ miles in about an hour -- is just really absolutely unconscionable , '' he said . The smaller Rosa Fire in Riverside County , 100 percent contained at 411 acres Thursday morning , was also probably arson , state officials said . Meanwhile , Los Angeles Fire Department investigators are looking into whether a man who was arrested on suspicion of arson in the San Fernando Valley may have had a role in any of the ongoing blazes , an L.A. police spokeswoman said . Catalino Pineda , 41 , was arrested Wednesday , Officer Kate Lopez told CNN . Witnesses told police they saw him lighting a fire on a hillside in the West Hills area of San Fernando -- northwest of Los Angeles -- then walking away , Lopez said . Pineda was already on probation for `` making excessive false emergency reports '' to police at the time of the arrest , Lopez said . His bail has been set at $ 75,000 , she said . The fire he allegedly set was brought under control , but now authorities want to find out if he had any role in the other wildfires . In San Bernardino County , John Alfred Rund , 48 , was arrested Tuesday evening and charged with setting a small fire along a rural roadside near Victorville . Rund was to be arraigned Thursday morning in Victorville . He was being held in lieu of $ 750,000 bail . The county 's district attorney 's office on Thursday also filed arson charges against Anthony Riperti , 47 , of Redlands . A statement from the office did not say when or where Riperti is accused of setting a fire . He is being held on $ 250,000 bail and will be arraigned later Thursday . The San Diego County Sheriff 's Department also arrested an adult and a juvenile accused by an anonymous tipster of starting a fire in Vista in the northern part of the county . In a written statement , the sheriff 's department identified the adult as Gorgonio Nava . The Vista Fire Department extinguished the blaze before it grew out of control , the statement said . Investigators have determined that the Grass Valley Fire in San Bernardino County was not caused by arson , and a preliminary investigation into the cause of the 10,152-acre Slide Fire seems to indicate arson was not a factor , sheriff 's spokeswoman Cindy Beaver said . E-mail to a friend .
L.A. Fire deliberately started in two places , official says . Rosa Fire grows to more than 25,000 acres . Santiago authorities investigate man arrested for suspected arson . Blaze has destroyed two structures .