The bodies of four people have been found at a property near Norwich, Norfolk Police said.
Officers attended an address in Allan Bedford Crescent, Costessey, shortly before 7am following a call from a member of the public.
Police forced entry to the property and found the bodies inside.
All four people are believed to be known to one another and enquiries are under way to formally identify them, police said.
A cordon is in place and forensics teams are at the scene.
Detective Chief Inspector Chris Burgess 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.”
He added: “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.”
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