How cann you find your laptop serial number if you dont have the laptop?

My sony vaio laptop was recently stolen. I talked to a cop and she said to bring her in the serial number so she could try and track it. But best buy apparently doesnt keep any record of serial numbers unless it was brought it for "services". And we cant find the box. So i was wondering if there is anyway you can find your laptop serial number without the computer its self and the box...?