What should I do? Stolen laptop ?

Ok. I got my laptop stolen from my apt last week. All along I have suspected it was the tenant downstairs. Well, me and him share the same Internet. I went online and typed in the modem's ip address. That brought up a list of all the computers in the network. My iPod touch was on there, my wireless printer, and 3 other computers. One of the 3 computers I don't remember seeing on there yesterday. So I type in the Mac address of that computer into a Mac address lookup site. The WLAN card's manufacturer came up as murata mfg co. Did some research on that company and turns out they make the WLAN card for HP. The laptop that got stolen was an HP. Could it possibly be my laptop and should I tip off the cops? They already filed a report, so they got the serial number of the laptop and everything.