Former EastEnders actress Sian Blake and her two young sons, Zachary and Amon, died as a result of head and neck injuries, police say.
Scotland Yard confirmed they were investigating a triple murder following the discovery of three bodies hidden in the garden of the family home on Tuesday.
Police sniffer dogs led officers to make the grim find at the property in Kent where “significant attempts” had been made to conceal the family’s remains.
Blake, 43, Zachary, eight, and Amon, four, have now been formally identified and post-mortem examinations have taken place.
Arthur Simpson-Kent, Blake’s former partner, is still being sought by police in connection with the murder inquiry and is believed to have fled the country to Ghana.
Photographs of Simpson-Kent, 48, were obtained by ITV News of Simpson-Kent at Kotoka Airport in the Ghanaian capital Accra – three days after he was quizzed by police over the family’s disappearance.
It is understood concerns about domestic violence were raised by a relative of Blake to British child abuse charity NSPCC on December 16, information that was passed on to the Metropolitan Police and Bexley Council.
A missing person’s investigation was launched on the same day after police visited the home.
Murder detectives helped lead a forensic search of the property on Sunday after being drafted in to assist the borough force.
Earlier, Blake’s sister Ava said Simpson-Kent will have to “answer to God” for his alleged actions.
Speaking at Scotland Yard, she said: “Unfortunately I believe Arthur was responsible for my sister and my (nephews’) deaths.
“I want him to face justice and explain why. It’s my nephews more than anything.
“My brother is angry. My cousins are angry and it’s because of the boys.
“They are angry about Sian, but the boys have devastated us. We have lost a generation. We can never replace them.”
Blake, 43, had motor neurone disease – a fatal, rapidly progressing illness which affects the brain and spinal cord – and was reportedly looking “very frail” before she vanished.
She was last seen with her sons in Waltham Forest, east London, on December 13 and officers spoke to Simpson-Kent three days later at the family home in Pembroke Road, Erith.
Ava Blake, 51, said her sister had told their mother, Pansy, that she wanted to get out of her relationship “a long time ago”.
Blake, who played soul singer Frankie in EastEnders, appeared in the BBC soap for 56 episodes between 1996 and 1997, reportedly quitting because of hostility from viewers towards her manipulative character.