Norfolk Police said officers were sent to The Warren in Cromer at 19:18 BST on Monday, having been alerted by the East of England Ambulance Service.
The couple were found unresponsive.
Det Insp Chris Burgess said: “We believe that those involved are known to one another and we are not currently seeking anyone else in relation to this investigation.”
Police said detectives were carrying out inquiries into the incident
A police cordon was put in place and Det Insp Burgess added that “detectives will carry out further inquiries to establish the full circumstances leading up to this incident”.
