Captain Daniel Mako celebrated his 44th birthday with friends on Saturday, then went home to pump three bullets into his wife.
His 43-year-old wife survived and is fighting for her life in hospital. The policeman killed himself after shooting her.
Nthabiseng Mako, a teacher at Bafokeng Primary School in Palm Springs in the Vaal, was admitted to Union Hospital in Alberton, Ekurhuleni, on Saturday night.
Captain Mako, 44, who was stationed at the Jeppe police station in Johannesburg, shot his wife with his service pistol at their Zone 6 Sebokeng home.
He then went to his mother's house in Zone 7, where he told his sisters to call his home to find out what had happened.
His sister Zoleka Dladla, 41, said Mako arrived at the house after 8pm, holding a firearm.
"After telling us to call his home he went outside, where he cocked the gun," Dladla said. "I tried to stop him but he threatened to shoot me and told me to back off.
"I ran into the house and heard a single shot being fired.
"When I ran back outside I found my brother lying on the grass. He was dead."
Dladla said her other sister called Mako's home. His 14-year-old daughter, Nomonde, was crying and said her father had shot her mother while she had been in another room. .
"I went there and found Nthabiseng bleeding on the floor in their bedroom," Dladla said.
Nthabiseng was airlifted to the hospital, where she was still in a critical condition yesterday.
The dead policeman's mother, Rebecca, 65, hurried back home from Vryheid in KwaZulu-Natal after hearing the tragic news.
She described her son as a quiet person and wondered what had caused him to want to kill his wife and himself.
The couple had been married for 19 years and had two children, Nomonde and eight-year-old Zandile, who was not present at the time of the tragedy.
Nomonde is now undergoing trauma counselling.
Dladla said the family was still recovering from the trauma of 2002 when her other brother, Fikile Mako, also committed suicide after killing his wife and mother-in-law in Sebokeng.
"I saw their bodies and I'm still traumatised and now this," Dladla said.
Vaal Rand police spokesman Captain Veli Mcera said an inquest docket had been opened.
He confirmed that the woman was shot three times and that Mako had committed suicide.