On April 22, 2004, former Cardinals safety Pat Tillman was killed in a friendly fire incident while on patrol. The specific details of his death and its aftermath are currently being investigated by the US Congress. Tillman was the first professional football player to be killed in combat since the death of Bob Kalsu of the Buffalo Bills, who died in the Vietnam War in 1970. Tillman was posthumously laterally promoted from Specialist to Corporal. He also received posthumous Silver Star and Purple Heart medals. On Sunday, September 19, 2004, all teams of the NFL wore a memorial decal on their helmets in honor of Pat Tillman. The Arizona Cardinals continued to wear this decal throughout the 2004 season.