Police in Costessey discovered the bodies of Bartlomiej Kuczynski, 45, a 36-year-old woman, and two children on Friday morning.
After a 999 call, all four were found in a home on Allan Bedford Crescent.
The woman and man underwent post-mortem examinations by the Home Office.
Police confirmed on Sunday that the woman died from multiple neck stab wounds, while Mr. Kuczynski died from a single neck stab wound.
Official identification has not yet occurred, according to Norfolk Police, who also stated that next of kin are receiving updates and assistance from specialized officers.
When police arrived at the scene and forcibly gained entry, the bodies were discovered at 07:15 GMT.
Investigators have stated that they were not searching for any additional individuals related to the fatalities.
Detective Chief Inspector Chris Burgess stated: “This latest information will only add to the distress and shock felt by members of the local community and it’s why, from the outset, we’ve been determined to carry out detailed and methodical enquiries to make sure we fully understand how this incident has happened.”
According to police, the two girls’ post-mortem exams would take place on Wednesday.
According to the force, there would be a police cordon at the location and officers would still be present on Monday.
The police made contact with the address on December 14th in relation to a missing person inquiry, which is why the incident has been referred to the Independent Office of Police Conduct (IOPC).
It was confirmed by Norfolk Police that it had twice referred itself to the IOPC for failing to send officers in response to a 999 call made at 06:00 by a man at the address before the bodies were discovered.
