I just wanted to clarify so there is no confusion. I am talking about two seperate bathrooms. The one with the tub was just recently remodeled. The one that is leaking is in my master bath. That one was remodeled a few years ago. I had a plumber replace the shower pan and hook up the fixtures then also. Both baths were done by two seperate plumbers. Unfortunately one was done wrong and the other was done correctly but I feel I overpaid.
Lastly, I know it is the drain because after the ceiling started leaking I poked a hole in the drywall. I ran the water in the shower and saw it dripping down the drain pipe. The flow was pretty heavy. I also opened the grating from in the shower and saw all the silicone that was put in around the original copper waste line. There appears to be about a 1/4 inch space between the old drain line and the new shower drain that was filled in with silicone. I tried calling the number on the invoice but it is not in service any longer nor is ther any listing in the phone book or 411 for this plumber. I would rather just move on and chalk that one up to experience.
The advise about the hardware store reference is one that sounds like a good start. I want to be sure I am not taken again so I was hoping for advise for the future plumber (number 3).... Thanks again for your help.