I've been puzzled by the AV's comment about the moustache and just had a thought.
Is it possible that before the official ID session the DA gathered lots of pictures of the lacrosse players, not just the team picture but high school yearbook pictures, newspaper pictures, etc. in an attempt to 'prime the pump' so to speak. Perhaps one of the players in those photos a moustache. When Crystal mentioned the one with a moustache she was referring to a picture she had seen earlier.
The guy she said had a moustache has never had one.