A man serving time for third-degree murder tried to escape from the State Correctional Institution Graterford on Thursday night, but he got only as far as the prison's power plant before he was apprehended, prison officials said.

According to Susan McNaughton, spokesperson for the Pennsylvania Department of Corrections, the inmate, who is "serving a lengthy sentence," did not return to his cell after exercise and activity time at the prison Thursday.

Graterford staff discovered the prisoner was missing during an inmate count at 9 p.m., McNaughton said.

Initial investigations show that the man, whose identity was not released, escaped the block by breaking a window and climbing onto the roof of a prison building, McNaughton said. The inmate was then able to get into the power plant, located within the perimeter of the prison complex, where he was taken into custody by officers around 11:30 p.m.

"Graterford staff acted appropriately and did a great job of apprehending the inmate," Corrections Secretary John Wetzel said in a statement. "We have a system of checks and balances in place, and that system worked. As soon as he was discovered missing during one of our many inmate counts, staff took appropriate steps and apprehended him within the secure perimeter."

According to McNaughton, Graterford has been locked down but visitations are still occurring. There is a plan in place to enhance security at the prison as staff prepare to close the 89-year-old facility and move to the State Correctional Institution Phoenix. McNaughton declined to disclose the date for the move due to security concerns.

State police are investigating the escape attempt and will determine whether to file charges, McNaughton said.

Staff writer Samantha Melamed contributed to this report.