A locking mechanism is provided having a frame for mounting on a door or other closure. A movable bolt is supported on the frame for movements between extended and withdrawn positions. An additional member is mounted on the frame for slidable movements generally parallel to the bolt. At least two locking means are incorporated into the locking mechanism, the first of which releasably connects the bolt to the member, and the second of which releasably positions the member with respect to the frame. With the first locking means engaged, the bolt is movable together with the member. With both the first and second locking means engaged, the bolt is locked in the extended position. A securing means engagable with the first locking means prevents release of the first locking means. The locking mechanism is particularly adapted for use on storage compartments wherein a renter of the compartment will gain access by way of the first locking means and the owner will gain access by way of the second locking means. The securing means will enable the owner to disable the first locking means to prevent free access by the renter.