stolen smartphone tracking If my  stolen samsung J1 (android 4.4.4)  got a ' hard reset' by the thief (so all the data and tracking app are deleted), how is it possible to track that device ? Does these facts help;


the thief has replaced my SIM by his own one.
the thief use his own gmail account now


,can help?
If that security is bypassed by a thief and it was not encrypted, only law enforcement can track it at that point, and call your service provider and report it stolen that way it's rendered useless and eventually will be busted for using/receiving stolen goods