AUSTIN — Rick Perry is the most security-minded, secrecy-obsessed governor in Texas history.So how come nothing stopped somebody from burning down his house?When I saw arson investigators carrying boxes out of the smoldering Texas Governor's Mansion early Sunday, I couldn't figure out why they were there. Surely, with all Perry's Double-Naught Spy security gear, nobody could get inside and burn his house.As it turns out, one arson expert agrees.Gerald Hurst of Austin, a chemist and nationally known expert witness, said Sunday that state fire marshals might have been too quick to blame arson. At first glance, the fire was probably a construction accident connected to the mansion remodeling project, he said."Most arson cases turn out to be accidental fires," said Hurst, often called as a defense witness in arson cases. "That fire's not going to be arson, unless there's somebody who's really" — uh, let's just say peeved at Perry.Gosh. If we're going to list all the people who are peeved at Perry, that's going to be a really long list. And it'll include as many Republicans as Democrats.But until State Fire Marshal Paul Maldonado tells what evidence he found, Hurst doubts the cause was arson.For one thing, the flames were originally seen through the second-story windows, where the roof later collapsed in the middle of the mansion behind the veranda.Rarely do arsonists go upstairs to start a fire."Absolutely not," Hurst said. "If you're going to take out a building, you start as low as possible. Start low and with lots of fuel to burn. Nobody would go upstairs."The 152-year-old mansion was in the middle of a $10 million remodeling project. Workers were scheduled to brace old floors, update the ancient plumbing, repaint and add a sprinkler system.If you recall, our governor is living at taxpayer expense in a $9,900-a-month estate in rural Travis County west of Austin during the remodeling.But on Sunday, he was gone on some globetrotting economic mission to Sweden, presumably trying to get Texas another Ikea store or a Volvo factory.The ancient electrical system might have caught fire, Hurst said. Or workers might have carelessly left something unsecured."If the air conditioning was off, and somebody was polishing woodwork, then the oil rags can start a fire," he said. "They're supposed to be kept in a tin box, but workers don't always do that."If somebody had set the fire, then the aerial photos would look different, he said."An arsonist will start multiple fires," he said. "You'd see damage all over." Claiming security concerns, state officials declined to explain what evidence led them to suspect arson, or how many deputies were guarding the mansion, or how anybody could get in at 2 a.m.Also, state officials refused to say how many security cameras were working.With Texas Democrats fresh off their state convention Saturday in Austin, the city was full of potential suspects. There were plenty of partisan jokes going around on both sides Sunday.But the real joke's on you and me. We have to keep paying Perry's rent.