A method and apparatus for locking a container. The present disclosure relates to a lock mechanism which comprises a latch assembly having a rod and an extension including a latch aperture, wherein the extension extends from the rod to position the latch aperture away from the rod. The lock mechanism further comprises a door assembly having a door aperture. Additionally, a support assembly is adjustably coupled to the latch assembly wherein the support assembly includes at least one arm which supports the latch aperture in alignment with the door aperture. The method for locking the container comprises adjustably coupling the support assembly to the latch assembly and attaching the support assembly to mount assemblies which are releasably attached to internal walls of the container. The door is moved to a closed position to position the door aperture adjacent to the latch assembly wherein the extension is in alignment with the door aperture to receive a lock.