After his arrest for involvement in the Collingwood Manor Massacre on September 16, 1931, Keywell was sentenced to life in prison at Marquette, Michigan and was eventually paroled at the age of 54 on October 21, 1965. He had a spotless prison record for 34 years before his life sentence was commuted. Because of the involvement of his brother, Phil Keywell, he was released early for good behavior. Harry married Sarah Keywell (nee Gold), and lived out his days as a productive member of society and family man, until his death of Alzheimer's disease on August 30, 1997.