Harry Keywell (December 8, 1910 – August 30, 1997) was a convicted member of Detroit's infamous Purple Gang, which terrorized Detroit during Prohibition. Chicago Police questioned him about the infamous St. Valentine's Day Massacre in February 1929, on the suspicion that Keywell acted as a lookout for the killers, however Harry had a cast-iron alibi for the day. Harry married Sarah Keywell (née Gold), and lived out his days as a productive member of society and family man, until his death of Alzheimer's disease in August 1997.