Plutarch's Dog Sacrificia

Plutarch says nearly all the greeks use a dog as the sacrificial victim for ceremonies of purification. And some at least make use of it even to this day. They bring forth for hecaty puppies, along with other materials for purification. So hecate's the goddess of the underworld. It may be because there's already a connection with purification that he thinks that. Or maybe the link with purification is made because that's the link it would have in greek culture.