Crime scene investigators are on scene at a house in Burgh Castle following an incident on Saturday.
An ambulance, police, and forensic officers were seen coming and going from a property in Louis Dahl Road in the village from around 11am.
An eyewitness said one person was taken to hospital, but that police remained on scene.
A spokesman for Norfolk Police said they believed it related to a medical issue but were treating it as a crime scene "just in case."
He said: "As far as we are aware the person was at home alone and had a medical episode, but until we know for sure we will treat it as a crime scene."
One person has been taken to hospital.
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