I can't even remember what type of L&O it was, whether it was SVU, CI, etc. All I know is that it was about this girl who went missing after going clubbing, and was killed, and the main suspect was a 17 year old boy who idolized frank sinatra and was the leader of a "gang" who played poker in club basements. They would seduce girls and kill them...or something. And the key to finding one girl, and prosecute the suspect was to find the body of another girl I think, but by the end of the first part, they still had not found it.
Any ideas on what the title was, or at least which L&O it was on? I really need to watch the second part, but I have no idea what the first was even called.