The body of a woman recovered from a university lake was fully clothed and the find is not being linked to any current missing persons investigations, police have said.
Detective Chief Inspector Dennis Lacey, from Norfolk Police, was speaking at the University of East Anglia after the find in a campus lake at about 8.40am today.
He said a post-mortem examination would be carried out this evening to establish a cause of death.
At this stage the woman has not been identified and it is not known how old she is but officers do not believe the find is linked to any ongoing missing persons reports in Norfolk.
Speaking at a press conference at the Norwich campus, Mr Lacey said: "We're in the early stages of our investigation but because of the nature of the recovery of the body, we are unable to put an age to the woman or how long she had been in the water.
"We are treating this as an unexplained death until we can establish the full circumstances of what happened."
Asked if the body was clothed, he added: "Yes, she was wearing what I would class as normal day wear."
Searches have been taking place throughout the day to establish where the woman entered the water and any trace of her belongings which could help with identification.
A university spokesman said: "As far as we are able to, we have accounted for staff, students and visitors on summer schools and conferences, and we have not been made aware of anybody reported missing."
Police were called to the lake after an angler spotted the body at 8.40am and the woman was recovered by 9.30am.
The beauty spot is about 200 metres away from university buildings and is popular with dog walkers and joggers. It is open to the general public as well as students.
Signs prohibit swimming and warn that the depth of the lake increases suddenly.
Brian Summers, UEA registrar, said all new entrants to the university were given safety advice telling them not to swim in the lake.
He added: "We occasionally find people going for a dip but we have regular patrols from our security teams.
"Generally we're able to point out that they shouldn't be swimming and they move out of the area.
"Even minor accidents are very rare at the university."
While some summer camps are currently being held on the campus, most students have left for the summer holidays.
Graduation ceremonies and leaving balls took place last month.