WILKES-BARRE, Pa. (AP) - Parts on an elevator door that gave way have become the focus of an investigation after a Pennsylvania jail guard and an inmate plunged about 60 feet down an open shaft to their deaths.

The parts in question are known as gibs. They are load-bearing devices that are meant to keep the doors from opening improperly.Luzerne County officials say the devices may have failed when first-year corrections officer Kristopher Moules and 27-year-old inmate Timothy Gilliam Jr. fell to their deaths on July 18.An engineering firm is investigating how the elevator door gave way after the guard and inmate exchanged words and then got into a fight on the fifth floor of the county jail.The Pennsylvania Department of Labor and Industry says its inspectors examine gibs when they certify elevators as safe.