The body of Sussie Ahlburg, 50, was discovered in the women’s open-air bathing ponds on Hampstead Heath on Monday.
The Sweden-born photographer had been reported missing by her family after failing to return home.
A Metropolitan Police spokesman said today: ‘Following the inconclusive post-mortem examination at St Pancras Mortuary on Wednesday 7 August, officers now await the results of further tests.’
An inquest into the photographer’s death is due to open tomorrow (9 August).
The Ladies’ Bathing Pond on Hampstead Heath, which is run by the City of London Corporation, is expected to remain closed while the investigation continues.
Staff say they are helping police with their enquiries.
‘The swimming community on the Heath is a very close one and our thoughts go out to the family and friends who have been affected by this news,’ reads a statement posted on the Hampstead Heath swimming ponds website earlier this week.