Police investigating the death of 31-year-old actress Natasha Collins are awaiting the results of a post mortem due tomorrow to establish how she died.
Officers suspect that Ms Collins, who was found dead by her fianc, the BBC children's presenter Mark Speight, died of a drugs overdose or heart failure brought on by drugs.
Mr Speight discovered her body in the bath of the flat they shared in St John's Wood, London, on Thursday. He was arrested on suspicion of murder and supplying the class A drug cocaine, and released on police bail until February.
His mother, Jacqueline, an art teacher, said yesterday: "There is no way on earth that Mark would do anything to harm Tash.
"I'm in absolute shock. I was only with them at Christmas. They both seemed fine and very happy."
Ms Collins took medication for fits she suffered after being hit by a car seven years ago, and Mrs Speight said she may have accidentally taken the wrong drugs.
A BBC spokesman said repeats of Mr Speight's show SMart had been dropped from this week's schedules, but that no other action had been taken.
The couple are believed to have met on the set of the CBBC show See It Saw It, which starred Ms Collins as a jester in the court of Mark Speight's king.
She had worked in theatre, television and film since graduating from drama school, appearing in the ITV drama Real Women and the BBC's 999 Flood Special.
Her agent, Lynsey O'Donnell, said: "Natasha was a really lovely, bubbly girl."Reuse content