The Living Dead at Manchester Morgue (1974)

Amid a string of grisly murders in the isolated English countryside, a detective zeroes in on two unsuspecting travelers as prime suspects. Unbeknownst to him, the true threat lies in the form of reanimated corpses, resurrected by an experimental ultrasonic radiation device from the Ministry of Agriculture, originally intended to exterminate insects. As the body count rises, the detective must unravel the mystery before the undead wreak further havoc, leading to a chilling confrontation between the living and the lifeless.