Go to your local police department and file a report and they should be able to access the insurance information through the party that owns the vehicle
How Can I Find Out Someone Car Insurance Info That Hit My Car I Have Her Tag # Vin # Driver Licence# Number?
Most states have that information stored in their database that is accessible through the Department of Motor Vehicles/Revenue Office, or possibly the Assessor's office. If you have a police report of the accident, this information should also be in there, as it is a requirement that they check the policy's validity.