Two people have been arrested after a seven-year-old girl died when the bouncy castle she was playing on blew about 150 metres away.
Two people were arrested on suspicion of manslaughter by gross negligence following the incident in Harlow on Saturday afternoon, Essex Police said.
East of England Ambulance Service said crews were called to Harlow Town Park shortly after 4pm to reports that a girl had been seriously injured when the bouncy castle she was on blew "some distance" away.
Families had gathered at Harlow Town Park in Essex on Saturday for the third day of the event organised by Thurston fun fairs over the holiday weekend.
The girl was treated by ambulance crews and the Herts and Essex air ambulance and taken to Princess Alexandra Hospital, where she later died.
Floral tributes have been left at the gate to the park where the tragedy took place yesterday.
A spokesman for the East of England Ambulance Service said: "Our thoughts are with the friends and family involved on this sad day."
A spokeswoman for the Health and Safety Executive said it was assisting police, the Press Association reports.
Last year a bouncy castle collapsed while children were playing on it during a funfair in the park.
Harlow Council officers visited the site following the incident last May and suggested a number of health and safety improvements, including better stewarding of the event.
It was reported at the time that three children had to be treated by paramedics when the inflatable castle collapsed on them.
After news of Saturday's tragedy broke, Conservative MP for Harlow Robert Halfon tweeted: "My thoughts and heart go to family."