On the morning of June 14, 1971, gunmen entered a house on Hazelwood Street in Detroit and opened fire shortly before 4:30 a.m. The attack left eight people dead at the scene; Robert Gardner, 28, was mortally wounded and taken by his wife to Henry Ford Hospital, where he died on June 20, 1971.

Police described the victims who died at the house as Gardner’s associates. Investigators believed Gardner was the primary target and that several shooters used a .30-caliber carbine, a .32-caliber pistol and a .45-caliber automatic. Law enforcement theorized the killings were retaliation for a March robbery in Detroit and that the slayings may have been a contract killing ordered by two Toronto drug dealers.

Despite an extensive investigation, the Hazelwood massacre remains officially unsolved and no arrests have been announced. Did anyone in Detroit at the time ever hear about suspicious visitors or vehicles on Hazelwood Street that morning?