Technically, none of the<em>Concordia</em>crew were chaos influenced!  :-)<br/><br/>Sergeant En's troops did indeed spend 5 years inside the warp, though he claims that they were shielded from any corruption by his dark pact.  Whether the dark powers actually kept their end of the bargain is another matter...<br/><br/>A scrutiny check on the prisoners will determine if they're in fact Imperial Guardsmen.  A simple check for Aquila tattoos will resolve things quickly, although the scourging makes it harder to be sure.