On December 6, 1921, Police Officer John McGrath was shot and killed when he attempted to search two juvenile brothers at 4936 St. Louis Avenue. As he began the search the elder brother produced a .32 caliber revolver and shot him in the chest. He was able to return fire, shooting five times before he collapsed but did not strike either boy. He died at the scene.

The two boys were apprehended and charged with Officer McGrath's murder. Both were acquitted after a jury concluded their confessions could not be used as evidence.

Officer McGrath, born in Ireland, was a U.S. Army veteran and had served with the St. Louis Metropolitan Police Department since February 13, 1920. He was survived by his expectant wife, Mary. Interred: Calvary Cemetery.