San Antonio police searched for a murder suspect from Visalia who drove off in a prisoner transport van after his guards went inside a store and left the keys in the ignition, Texas authorities said. Richard Lacy Letner Jr., charged in the torture-murder of nurse Ivon Pontbriant of Visalia, kicked out a passenger-door window in the back of the van and managed to drive away, said San Antonio police spokeswoman Sandy Perez. Letner, 27, drove about a block before using the keys to unlock his shackles and flee on foot. He was one of nine prisoners being transported by Interstate Extraditions of Bloomington, Ill., a private company that uses former law enforcement officers to transport 3,000 prisoners a year across the nation. "I would certainly consider him very dangerous in light of the escape and because the information from the (murder) case alludes to that," Visalia Police Sgt. John Gomes said.