FBI interview Barry Shuman
Shuman lied to the FBI when he said Sharon Sargent said she was afraid of Richard Sargent. That is not what Sharon said. In her July 24, 1984 interview she told Shuman that she was afraid of Percy Sargent:

David Dupray and Bob Rideout also told Shuman that they were afraid of Percy Sargent.   So why do the detectives lie to cover for Percy Sargent and try to convict men innocent of Mike's murder?