I am so sorry this happened to you and your sister. I had my bike friday stolen locked to a bike rack at work, so I understand how you feel. Again, clearly planned, someone brought something to cut the lock with while I was inside at work, and it happened right behind a security booth......... I did not recover my bike, but was advised to check pawn shops, newspaper ads, criaigs list, ebay. And yes, if you recorded the serial numbers file a police report. Also, I know they weren't expensive bikes, but you might be able to recover something on your homeowners/apartment insurance. Ask your LBS to give you a quote for REPLACEMENT bikes if you have replacement coverage. I also sent pix to all the LBS in case someone brought it in for service, and our bike club ran a pic in our newsletter. The more people looking, the better the chance of recovery. I do know several people that found their stolen bikes in pawn shops.