in the first case, david leon riley was pulled over on august 22, 2009, for expired registrations tags. during the stop, the san diego police officer also found that riley was driving with a suspended driver's license. the san diego police department's policy at the time was to tow and impound a vehicle after stopping a driver with a suspended license in order to prevent the driver from driving again. additionally, department policy required the officers to perform an inventory search of the vehicle, which in this case led to the discovery of two handguns under the hood of the vehicle. later ballistic testing would confirm that the handguns were the weapons used in a gangland murder on august 2, 2009, for which riley had been a suspect. although eyewitnesses to the shooting claimed that riley could have been one of the shooters, they declined to give a definitive positive identification of riley as one of the shooters. however, this was not known by officer dunnigan at the time of riley's traffic stop.