Following their visit to Jacob's cabin, Ben Linus brought John Locke to the mass grave to show him the place where he "came from". Ben explained that the corpses were members of the DHARMA Initiative, the group he was a member of before he joined the Others. Ben claimed that when it became clear to him that the DHARMA members would be purged, he did what was necessary to stay alive. After this revelation, Ben shot Locke in the abdomen and left him for dead in the pit. ("The Man Behind the Curtain")
Locke after being shot by Ben.
Locke came to and prepared to shoot himself with a gun he found on one of the corpses. He was stopped by what appeared to be "Walt, only taller," who instructed him to get up as there was work to be done. ("Through the Looking Glass, Part 1")
Approximately a week later, Locke returned to the mass grave with Hurley and Ben after being told to find Horace in a dream. Searching through the bodies, Locke found Horace's blueprints containing the location of Jacob's cabin. ("Cabin Fever")
- One of the corpses appears to have a gunshot wound to the head, indicating either that the use of toxic gas wasn't the only method used to kill off the members of the DHARMA Initiative or that bodies continued to be disposed of in the pit after the gassing.
- Over forty people were killed during the Purge. ("Through the Looking Glass, Part 1")