A police officer and her three-month-old baby were shot dead in their house in Centurion on Saturday, police said.

The woman's 12-year-old son was rushed to hospital with gunshot wounds. He was in a critical condition and rushed to the Unitas hospital in Centurion..

"She was a captain at the Pretoria Criminal Records Division and she stayed alone with her two children," said Inspector Wanda Olivier.

Olivier said Captain Annake van Niekerk's body was found at 1pm by her ex-husband who came to the house in The Reeds to fetch his son.

When police arrived at the scene, the officer's service pistol was found next to the captain's body. It will be sent for forensic testing to find out whether it was used in the murders.

The police do not suspect robbery as the motive..

Police were still combing the scene for clues.