Decades have passed, but the search for answers has not dimmed in the case of Mary Ellen Prater and Alvin Loyd Prater, a young couple whose lives were cut tragically short on an isolated road in Sunol. The Alameda County Sheriff's Office turned to social media to shed new light on this cold case. In a post on the sheriff's office's official page dated yesterday, authorities reminded the public of the grim discovery made on Sunday, August 25, 1974, where both Mary, 20, and Alvin, 27, were found shot to death on Old Vallecitos Road. Both had been recently married and were last seen alive at a family gathering the week before their bodies were discovered.
With the hope that time may have brought forward new witnesses or evidence, the Sheriff's Office urges anyone with information to come forward. The social media post from the sheriff's department encourages those who may know something to contact their Cold Case Homicide Unit directly. Officials underscore the importance of direct witness accounts and anonymous tips in piecing together what happened to the couple in 1974.
COLD CASE ANNIVERSARY pic.twitter.com/B8iMHC7on2
— Alameda County Sheriff (@ACSOSheriffs) August 25, 2025
Those wishing to provide information are asked to contact the investigators at (510) 667-3661. An Anonymous Tip Line is also available at (510) 667-3622 for those who wish to provide details without revealing their identity.
