A convicted murderer who escaped from an Iowa prison this week by using a homemade grappling hook to scale a 30-foot limestone wall was captured Thursday in Illinois. A second inmate remained at large.

Martin Moon, 34, was caught after he was found sleeping in a stolen car in the town of Chester, near an Illinois prison. He told investigators he was on his way to Tennessee but gave no reason, authorities said.

Moon and Robert Joseph Legendre, 27, broke out of the Iowa State Penitentiary in Fort Madison on Monday night.

Authorities said the two used the homemade hook along with a rope fashioned from upholstery materials taken from the prison furniture shop. They went over an unguarded section of wall and somehow got around a wire that is supposed to activate an alarm when touched.

Based on Moon's account, police believe Moon and Legendre immediately split. A nationwide search was under way for Legendre, who was in prison for attempted murder.

Police in Randolph County, Ill., discovered Moon after officials at Illinois' Menard State Penitentiary called to report a car parked nearby. When an officer stopped to run on a check on its license plates, Moon drove off, but crashed into a fence. Moon then tried to run away before being caught by a police dog.

Moon agreed to be returned to Iowa, police said.

An investigation of the escape has begun, Gov. Tom Vilsack said. "There were a series of mistakes that were made," he said.

A corrections official has said the guard tower near the spot where the inmates went over the wall was unmanned at the time because of budget cuts.

Moon was convicted of murder in 2000 for shooting his roommate during a drug deal in 1990. Legendre had been transferred from a prison in Nevada, where he was convicted in the beating of a cabbie.