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
Simon's Blog - Home Sweet Home
Monday night's forecast for the east of the region
Monday night's forecast for the west of the region