CONCORD, N.H. (AP) — New Hampshire state police are investigating how convicts at the state prison in Concord hacked into sensitive Department of Corrections records and whether they corrupted internal files.

Corrections spokesman Jeffrey Lyons says the security breach was discovered last week by a staff member working in the prison industries shops. He said about two dozen inmates have access to a cluster of computers on a closed network that tracks only industries contracts and billing.

But a staff member noticed Aug. 24 that a cable was linking one of the inmate computers to a staff computer that can access all Corrections Department data systems.

The prison industry shops reopened Wednesday after a five-day shutdown, but the inmate computers remain off limits.

Lyons says investigators haven’t pinpointed when the breach occurred.

Copyright 2012 The Associated Press.