December 2, 1929, Officer Dingman had been on patrol at 31st Street and Jackson Avenue, when he pulled up next to a car carrying three men - John Watson, Joe Hershon, and Charles M. Curtis. He attempted to approach them, and Watson and Hershon opened fire. Dingman was mortally wounded, and died December 4, 1929. The three men were found and arrested, and it was learned that they had been released from jail that October and were known gangsters. The three, as well as a Henry Hicks and Morris Grimm, confessed to at least fifteen recent crimes, and Watson confessed to being the one who fatally wounded Dingman.

Charles H. Dingman Jr. had been a member of the police force for six years.