Bartlomiej Kuczynski, 45, died from a wound in his neck while the woman – who has not been named but was aged 36 – had an unspecified number of wounds, also in her neck.
They were found in Costessey, near Norwich, on Friday morning with the bodies of Jasmin Kuczynska, 12, and her sister, aged seven.
Norfolk Constabulary said in a statement that post-mortems were carried out on the adults yesterday. Those for the girls will be done on Wednesday.
Det Chief Insp Chris Burgess, who is leading the investigation, said: “We remain satisfied no one else was involved in this incident.”
Earlier, a woman whose son knew Jasmin described her as a “very, very sweet girl” who had a “calm and cool energy”.
Nina Crisan said “she was just a lovely, lovely kid” and that the incident had come as an “absolute shock” to the community.
The incident has twice been referred to the Independent Office of Police Conduct.
The first case regards police contact at the address on December 14, relating to a missing person enquiry.
The second is in relation to a 999 call made from a man at the house shortly before the bodies were found. No officers were sent.
