He sprayed a cop in the face with pepper spray at a traffic stop (LONG before the Smart abduction) and fled.
This conveys two things:
1) The cops HATE people that attack them and are quite happy to use any association with the Smart case to get this guy, and
2) Stealing several cars to flee the police and evading the police prior to that isn't any sort of evidence at all that this guy is actually connected to the Smart case.