Man charged with arson in small California fire Story Highlights NEW: Charges filed against man who allegedly set fire and walked off NEW: Catalino Pineda one of five arrested in arson investigations this week Arson investigations continue across multiple California counties No suspects in Santiago arson; reward fund at $250,000 (CNN) -- The Los Angeles County District Attorney's Office filed arson charges Friday against a 41-year-old Sun Valley man who witnesses said set a fire in the West Hills neighborhood and walked away. Catalino Pineda is one of five people who have been arrested in arson investigations this week, but none of them has been linked to the major wildfires raging across Southern California. Pineda was arrested Wednesday after witnesses said they saw him lighting a fire on a hillside, police said. The fire was quickly extinguished. The witnesses followed Pineda to a nearby restaurant and called police, who arrested him. Pineda was expected to be arraigned in Van Nuys Superior Court Friday, Deputy District Attorney Steven Frankland said. Pineda is charged with one count of arson of a structure or forest. He is being held on $75,000 bail and faces up to six years in prison if convicted. Arson investigations continued across multiple California counties on Friday, as firefighters gradually gained control of wildfires that have burned nearly half a million acres this week. In San Bernardino, east of Los Angeles, John Rund, of Hesperia, was arrested Wednesday on arson charges after a witness reported seeing him in brush near the starting point of a fire Tuesday, the sheriff's department said. That fire was quickly put out by passers-by. Investigators are trying to determine if Rund, 48, may have ties to other wildfires. He is being held on $750,000 bail. The San Bernardino County District Attorney's Office on Thursday 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. In San Diego County, the sheriff's department this week arrested an adult and a juvenile allegedly seen by an anonymous tipster 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. Orange County officials still have no suspects in their investigation of the origins of the 27,000-acre Santiago fire. The fire was deliberately started by someone with apparent knowledge of arson, a fire official said Thursday. Watch residents describe their feelings about arsonist » The Santiago fire has destroyed at least 22 structures, including 14 homes, and caused $4 million in damage, the California Department of Forestry and Fire Protection said. By Thursday night, it was 30 percent contained. Watch the Santiago flames rage » A $250,000 reward has been offered for information leading to the arrest of whoever is responsible. 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 11,675-acre Slide fire seems to indicate arson was not a factor, sheriff's spokeswoman Cindy Beaver said. More than 1,600 homes have been destroyed in the past week by Southern California wildfires. All AboutOrange County Arson What in the world is going on in these people's minds that do things like this????