In the car Hurley finds a map and Swayer says that them DHARMA feaks, which was funny. was going to build something.
I think that the DHARMA initiative were starting to build stuff around the island.
So Roger could of been one of the first dharma people on the island.
Or maybe the others killed him. Because pacthy did say that there so a war with dharma and the hostiles(Others). So maybe that was one of the killings