Is a restored iPhone traceable?

I got a VERSION iPhone 4 from a friend. I honestly think he stole it. I'm interested in keeping it. I took it home and restored it.yet it still has a signal. How can i get rid of that? Do i just need to wait for the original owner to deactivate it? P.s there's no sim card because it i verison.

Yes.
and once restored on your PC, apple has the serial number and the ip address where it was restored.
if its stolen take it to apple and have them return it.

Don't ask us to help you STEAL.

Watch this movie, i think that will help you.