gary foye told me that he saw these two guys in butch's mercedes convertible. >> foye thought it would be odd that two young men would be driving casey's car. >> they took off towards hollywood boulevard. gary foye followed them and looked at them. he said one of them looked latin, and the other guy, i really couldn't see, but he wasn't latin. i'm thinking, like, this guy is gold, now. he actually saw them. >> police were convinced if they found the men who drove that car they had their killers. as investigators continued to comb through butch casey's house, they discovered a cache of videotapes hidden in the bedroom. they appeared to be sex tapes, filmed from a secret camera mounted above casey's bed. an officer then noticed a souvenir film slate on a high bookshelf in the living room. >> he looked behind it, and it was a camera. and he discovered that it was attached to a vcr. >> i was outside. they were like, come here, you have to see this. and took the tape. popped it into the tv and it starts up. and there's butch casey walking around the night before, getting ready to go to work