I went through this process several years ago. In a "nut shell" I would follow the instructions provided by ICBC.
http://www.icbc.com/cs/Satellite?c=ICBC_FAQ_C&cid=1225925939954&pagename=ICBC%2FICBC_FAQ_C%2Ficbc_FAQQuestion&proxied=true#1225925939954Once the attached form on the website is submitted along with a $7 cheque, ICBC will eventually provide you with information on the last registered owner. The information provided will be accompanied with very specific instructions. Make sure you follow them. This will involve sending a double registered letter, which will result in it either being accepted or returned. Once again depending on the situation there are very specific instructions. In my case the owner was still at the address, which added a layer of complexity. Nonetheless, I followed the instructions and with the cooperation of the last registered owner I was able to register the car in my name.
Make sure you keep all documentation as you work through this process. Also if you are unfortunate and do get a response from the last registered owner. I would recommend going to Metrotown (if you are local) as they have a Notary and ICBC agent side by side.
The whole process took about 5-6 and $400 to complete.
It appears as your biggest challenge will be the lack of a "bill of sale", as this is required.
I hope this helps. Good Luck!!