Any military records available for 1943?

We are still searching for my husband's birth father. We know he was an MP in the army in late 1943, early 1944. We are 90% sure he was stationed in the Wayne Michigan area at this time, the other possibility was that he was in Sidnaw, Michigan at the German POW Camp, though this is not likely. We don't know his name, but his age in 1944 was 31. If anyone knows how to find any listing of MP's in the army in any of these locations, it would be greatly appreciated. We have gone the route of the CI, and came up empty. His birth mothers name was Nora Vern Bennett. Thanks for any help.