Thirteen teenagers locked up at a Tennessee detention facility overpowered a correction's officer and broke out late Friday, an escape that comes only weeks after another successful breakout despite efforts by jail staff to shore up security. While 12 young men were recaptured within hours the last teen remained at large through Saturday.

A guard at Nashville's Woodland Hills Youth Development Center, which houses males 13 to 19 years of age with at least three felonies, was attacked by the group, which used his keys to escape their dormitory. Thirty-two teens escaped from the same facility Sept. 1, and another group broke free through a window in May.

Two of the 32 teens who broke out Sept. 1 are still at large. Timothy B. Willis, 16, whose record includes theft, assault and robbery, is the only teen still on the loose from Friday's escape.

“Since the last set of escapes, the department has been rapidly upgrading security,” the Tennessee Department of Children's Services told CNN. “Aluminum panels that students were able to kick through have been replaced with steel ... a project to reinforce the perimeter fence with concrete at the base is nearly complete.”

Fourteen officers were working at the time of the break-out, but staff members told local reporters they are only equipped with radios, not pepper spray or any other weapons. The delinquent youth aren't locked in cells, as inmates at an adult facility would be, and a statement from the TDCS said the guards "have few methods to control the youth.”

The remaining 52 youth were secure in their dorms at the time of the escape, though officials speculated the group of 13 tried convincing more to come with them. Woodland Hills personnel said they will again evaluate safety protocol and increase the size of the guard staff.