The daughter of Holby City star John Michie apparently took an "illegal substance" before her death at Bestival, her family has said.
The body of Louella Eve Fletcher-Michie was discovered in a wooded area on the edge of the festival site at Lulworth Castle, Dorset, on Monday.
Her family said their "hearts are broken by the horrific tragedy" and Ms Michie "(appears) to have taken an illegal substance".
They repeated they did not believe there to have been "any malice" involved in her time at the festival.
In the statement to The Sun newspaper they added: "We would appreciate cautious and sensitive reporting until the facts are known."
A man arrested on suspicion of murdering the 25-year-old and supplying a Class A drug has been released under investigation, police said last night.
A Dorset Police spokesman said: "An initial post-mortem examination took place on September 11, which showed no clear signs of an assault.
"However, further examinations will need to take place over the coming weeks, including toxicology, in order to establish if there are any substances in her system or other suspicious circumstances.
"A 28-year-old man, who was known to Louella, was arrested on suspicion of murder and supply of a controlled class A drug. He has now been released under investigation."
A police spokeswoman declined to comment on which Class A drug the 28-year-old man had been arrested on suspicion of supplying.
Former Coronation Street actor John Michie, 60, previously told The Sun the family had lost their "angel" and described the death as "a tragic mistake, a tragic accident".
"She touched so many lives. She was so very positive, so bright, so out there. She had such energy. The tributes to her have been incredible," he told the newspaper.
On Monday, the organisers of Bestival said they were "devastated" by the death and were supporting police with the investigation.