He knew he had something Martin wanted. He knew what Martin and his partners did for a living. There was already the suspected breach, and finding Werner’s card in his office settled that briefly. When the mere mention of a computer came up in this scenario, Cosmo reconsidered how likely it was to be a simple misunderstanding versus his former close friend being involved.
Minor correction: I don't think they found Werner's card in his office. There just didn't seem to be anything amiss in there when they checked. As Werner said, "Well, uh, everything seems to be in order."
