A prisoner of the Centre County Jail escaped yesterday while visiting a drug and alcohol treatment center.

Officer Michael Poorman said some of the prisoners are dropped off at the center and Mark Melfon walked away during his stay there.

"He's at large -- they're looking for him now," Poorman said last night.

Melfon is described as a stalky male with green eyes and brown hair. He weighs about 220 pounds and is 5 feet, 10 inches tall.

Prison Warden Gerald Wilson said Melfon was being held at the prison for parole violation and theft.