Four bodies have been found at a home in Costessey.
Police were called to Allan Bedford Crescent shortly before 7am following a call from a member of the public.
Police forced entry into the property and found the bodies of four people inside.
All four people are believed to be known to one another and enquiries are under way to formally identify them.
READ MORE: Live updates after four bodies found at home in Costessey
A police cordon is in place in Allan Bedford Crescent and detectives from the Norfolk and Suffolk Major Investigation Team are leading the investigation.
Forensic investigations are also being carried out.
Detective Chief Inspector Chris Burgess, from the Norfolk and Suffolk Major Investigation Team, said: "Our investigation is in the very early stages and this is clearly a very distressing and tragic incident.
"While we’re following a number of lines of enquiry, at this time we believe this is an isolated incident.
"I understand that news of this incident will be shocking to the local community and as soon as we can we will release more information."
A 32-year-old man who lives on an adjoining road said: "When I was dog walking this morning I saw the cordon at about 8am.
"This is a very quiet neighbourhood and I’ve never seen anything like this before here.
"This is something like you see on the TV I suppose, so it seems all quite surreal."
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