Parker, along with Bert Gunnarsson, helps run the refugee settlement in Aerotech Office Park. He was married at one point, but his wife left him, something Keith is quick to point out when Parker arrests him. Parker then demonstrates that he may be slightly unstable, gunning Keith down a second later.
The Coyotes: Parker will inform the player about missing refugees.
Keith's Caravan Charade: Keith is a crooked caravan player. Proof of either Keith's dealing or cheating can be found in Aerotech Suite 200 and brought back to Captain Parker for a small reward. He will then go to arrest Keith, who will unwisely taunt the Captain by mentioning his failed marriage.
xbox360 Sometimes, if you obtain the evidence of Keith's cheating or dealing and show it to Parker, he will ask if you want to come prosecute him. Accepting makes Parker walk out the tent but will be nowhere to be seen. He will have returned to sleep and Keith will be dead on the mattress without any contact from Parker.
pc Sometimes, if the sequence where you follow Parker to arrest Keith occurs at night, when entering the Aerotech 200 Suite where Keith is, Parker will glitch and stop walking, making the quest impossible to finish. You can still talk to Parker, however. If you wait until morning, Parker will return to his patrol like nothing happened.
pcxbox360 Sometimes Captain Parker will open fire on Keith's already dead corpse after you speak with him about the death. If you open dialogue with him again, he will again fire on the corpse. This can be repeated over and over - talking to Captain Parker and he then firing another magazine into Keith's corpse. Sometimes he'll even switch magazines to continue firing.