stolen phone

my iphone was stolen 2 weeks ago. I can still locate my phone thru find my iphone. The problem is, I dont know what to do next. I am about to report this to our local law enforcement but I believe they might ask for the IMEI or serial number of my phone in which I wasn't able to list. That stolen phone was actually a replacement phone from Apple since my original was broken and Apple had it replaced for free. Can anybody give me suggestions on my problem? I badly need help. Thanks!