Detective Chief Inspector Ian Pollard from the Surrey and Sussex Major Crime Team, who is leading the investigation, said: "While initially it was thought that we were dealing with a sudden death, officers became increasingly suspicious of the circumstances.
"As yet, the cause of her death is unexplained and we are awaiting the results of a post mortem that will take place on Tuesday.
"However, our enquiries lead us to believe that this was not a natural death and a murder enquiry has been launched."
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James Wright has Monday's forecast for the east of the region.
James Wright has Monday's forecast for the west of the region.
At least 13 people have been injured after a car was driven into a nightclub in Gravesend.