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."
More top news
Dry with sunny spells to start. Warm with hazy sunshine this afternoon
A dry and bright start with long spells of sunshine into this afternoon and feeling fresher
Fine this evening, then dry overnight with mist likely in places. Sunny spells tomorrow morning with hazy sunshine in the afternoon