Detective William Hayes was shot and killed while searching a suspect on Nineteenth Street near Lucas Avenue.

On February 23, 1919, Detective Hays and two special officers, Michael Roche and William Aylward, heard gun shots in the area and went to investigate. Detective Hayes stopped a man who was one of two men running south on the west side of the 1900 block of Nineteenth Street and began to search him. The suspect, Joseph Priest, suddenly stepped back, produced a revolver from his coat sleeve, and shot Detective Hayes in the stomach and right leg. Detective Hayes fell to the sidewalk and then the gutter. He was transported to a local hospital for treatment. The suspect was apprehended and taken to the hospital where he was positively identified by Detective Hayes before he succumbed to the gunshot wounds at 7:24 pm he received on February 21st. The man was convicted and sentenced to life but won a second trial in which he was acquitted.

Officer Hayes had been with the St. Louis Metropolitan Police Department for six years and was assigned to the Carr Street Detective District. He was survived by his wife and four children. After his death, his wife was appointed as a female detective.