William Erwin Walker, also known as Erwin M. Walker and Machine Gun Walker (born Erwin Mathias Walker; October 6, 1917− October 7, 2008), was an American police employee and World War II United States Army veteran who is remembered for a violent series of thefts, burglaries, and shootouts with police in Los Angeles County, California, in 1945 and 1946, one of which resulted in a fatality. The film He Walked by Night (1948) was loosely based on Walker's 1946 crime spree.