When Det. Castlebeck and Det. Drycoff are searching the warehouse with the blacklights. When Det. Castlebeck notices the list of 50 cars, he says "yes, yes". When he says yes the first time pause the movie and use frame advance. Right before he says yes for the second time, you will see the cord for the blacklight going down his sleeve. Whoops!!
I saw that cord clear as day while watching it on HBO after I saw this posting...I never saw it before but it was obvious that it was intended to be hidden in his sleeve.