Wife In Car Accident, Have Plate And Vin But No Name Or Insurance

Location: Michigan. My wife was hit by another car blowing through a stop sign. Clear case of other driver at fault but the police weren't called. Instead of insurance information, he gave my wife the registration that has the plate and VIN, but not his name or insurance. The police can't or won't match that to a name. It comes back only to the leasing company. Other than concluding my wife wasn't at fault, the police report is basically useless. The leasing company won't release his information. Our insurance doesn't have his plate or VIN in their system and says Michigan is a non subrogate state, so can't/won't track him down. Do we have any ability to track this guy down? Would an attorney be able to subpoena the leasing company for his information? Anything we can do to not file with our insurance?