Ex-EastEnders actress Sian Blake and her two young sons died from head and neck injuries, police have revealed.
Scotland Yard confirmed they were investigating a triple murder following the discovery of the three bodies in the garden of the family home on Tuesday.
Ms Blake (43), her sons Zachary (8) and Amon (4), have been formally identified and post-mortem examinations have taken place.
Scotland Yard said there had been "significant attempts" to conceal their bodies.
Arthur Simpson-Kent, Ms Blake's former partner, is being sought by police. He is believed to have fled to Ghana, with ITV News obtaining pictures of him at an airport in the African country.
Detective Superintendent Paul Monk said: "We are continuing to appeal for information about Arthur Simpson-Kent, who was last seen by police officers at his home on December 16.
Earlier, Ms Blake's sister Ava said Simpson-Kent would have to "answer to God" for his alleged actions. "Unfortunately, I believe Arthur was responsible for my sister and my (nephews') deaths," she added. "I want him to face justice and explain why.
"We have lost a generation. We can never replace them. I want him to be brought back to justice. He'll have to answer to the courts of this land and to God eventually. I don't know what is going through his mind."
Ms Blake had motor neurone disease - a fatal, rapidly progressing illness that 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.
Ms 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.