Using the Online Citizen Reporting System allows you to submit a report immediately and print a copy of the report for free. Using this online citizen police report system allows you to submit a report immediately and print a copy of the police report for free.Call 925-935-6400 if: There are injuries; The other vehicle's license plate number is known; The current location of the other vehicle is known. If it is a non-emergency, call (925) 646-2441. Q: What if this happened in another city? If you are having a police or medical emergency, call 911. Any non-emergency, suspected crime should be reported to your local law enforcement agency. Contra Costa County is a vibrant, diverse community in Northern California, rich with economic opportunities, events, and entertainment. Consider new ways for emergency call responses. Antioch began exploring the development of a local non-police response system and Contra Costa County residents.