Four people were found dead in a home in Cosetessey early on Friday morning in what has been described by police as a "devastating incident".
Here is everything we know so far about the deaths.
Four bodies are found
Police were called to Allan Bedford Crescent in Queen's Hill at around 7.15am on Friday after a member of the public raised concerns for the welfare of people inside.
Officers forced entry into the property and found the bodies of four people.
A cordon was put in place and forensic teams were continuing investigations at the house over the weekend.
It was confirmed that two young girls, a 45-year-old man and a 36-year-old woman had been found at the property.
While the man and two children lived at the address, the woman was not a permanent resident.
Police said they were aware of a weapon having been found near the property but did not believe it was connected to this incident.
Family identified locally
The man living at the property was identified locally as Bartlomiej Kuczynski, 45, a structural engineer.
The two young girls have since been named as Jasmin Kuczynska, 12, and Natasha Kuczynska, 8.
They attended Taverham High School and Queen's Hills Primary respectively and both schools have offered "extra support" for staff and students in the wake of the incident.
The 36-year-old woman has been named as Kanticha Sukpengpanao, the maternal aunt of the two girls.
According to reports, she had arrived in the UK on December 27 to stay with her sister Nanthaka - the girls' mother - and the family at the house.
Nanthaka is understood to have been at work at the hospital at the time of the tragedy.
Ms Sukpengpanao's friend Naty Wathanakul told The Mirror she had been due to fly home at some point next month.
Police reveal 999 call was made
an hour before the family were found dead.
It was revealed this weekend that police did not respond to a 999 call from the addressIt is understood that Mr Kuczynski made the call at 6am but police did not deploy resources to the address until receiving another call at 7am from a concerned member of the public.
The Independent Office of Police Conduct (IOPC) is now investigating the force in relation to the call.
The IOPC's regional director, Charmaine Arbouin, said: "During that call the man expressed concerns for his own mental state saying he was confused.
"He was advised to seek medical advice and police did not attend.
"At around 7am the force received a call from a dog walker concerned for the welfare of those within the home."
The IOPC investigation also relates to police contact at the address on December 14 in connection with a missing person enquiry.
Neighbours said Mr Kuczynski himself had been reported missing and that police had used a drone to search the area with the father later found safe.
It is understood that officers took him to the Norfolk and Norwich University Hospital for assessment, but that he left the Colney site unescorted before this could be carried out.
Neighbours said the 45-year-old had been struggling with mental ill health for several months, for which he had been asking for help.
Shadow home secretary Yvette Cooper said it was "deeply troubling" that the 999 call on Friday was not responded to.
Post-mortems carried out
Post-mortem examinations were carried out on Mr Kuczynski and Ms SukpengpanaoMr Kuczynski died as a result of a single stab wound to the neck while Ms Sukpengpanao died from stab wounds to the neck.
Post-mortem examinations on Wednesday found the cause of death for both Jasmin and Natasha was knife wounds to the neck.
Detectives also confirmed that the deaths of Ms Sukpengpanao and the two girls are being treated as murder.
Detective Chief Inspector Chris Burgess, who is leading the investigation, said: "We understand how incredibly shocking this incident is for all involved and for the wider community and that this latest update adds to the sense of heartbreak.
"Our thoughts are with the family of those found at the property grieving such a traumatic loss.
"We would like to thank the community for their help and will continue to provide reassurance patrols in the area. A cordon will remain on at the address whilst we finalise our detailed examination of the scene."
Police chief calls for "deeper review" into force
a full independent review of the force’s control room in relation to the 999 call made by Mr Kuczynski.
Norfolk’s chief constable has asked forChief constable Paul Sanford said he had listened to the 999 call but could not comment on it as the IOPC is investigating all the circumstances around the handling of the tragedy.
Mr Sanford revealed that he has asked His Majesty’s Inspectorate of Constabulary, who are due to carry out a routine inspection of the force next month, to extend the remit to carry out a "broader and deeper" investigation of the control room.
Mr Sanford said it was very unusual to ask for a more robust inspection.
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