Police are investigating the murder of 87 year old Anne Redman, who was found dead in the backyard of her Seacliff home at about 5.30 on Australia Day.
Detectives believe the power was cut to her home that evening.
Police have charged four people over the deaths of two other people found dead in South Plympton and Osbourne overnight.
Two men were arrested after the body of a 29 year old man was found in Vincent Street at about 2am.
While another man will face court today charged with the stabbing murder of another man at osbourne at about 2.30 am.