Raphael Schumacher, 27, was appearing in Mirages, an experimental theatre production staged in Pisa when the incident occurred.

Doctors said Friday that the 27-year-old is now clinically dead, after spending nearly a week in a coma.

While police are now satisfied the incident was accidental, they have begun investigating the theatre for any signs of negligence.

It was only when a medical student in the audience realised Mr Schumacher was actually being strangled that he was detached from the noose.

On Thursday, Pisa Today reported doctors as saying his condition was worsening and he was not responding to treatment.

Reports indicate that a box on which Schumacher was supposed to stand while he wore the noose was moved. He was also supposed to wear a body harness.

`The noose should have been fake and a harness should have caught him if he fell,` a source said. `I cannot explain how an incident like this happened.`

Mirages is a six-scene immersive performance staged in different parts of the theatre, with the audience walking betwen them.

Schumacher`s ill-fated act took place in the courtyard of the theatre, where a rope had been suspended from a fig tree.

He was wearing a mask for the scene, which was performed successfully earlier in the same evening, but a recent medical graduate saw him trembling and realised something was wrong.

`We are shocked,` Gabriele De Luca, the art director at the theatre, said. `No one, not even us, understands how this happened and it will be up to the police to shed light on it.`

However, De Luca told Italian newspaper Il Giorno that Schumacher changed the script at the last minute, opting for the noose instead of gunshots.

`The original monologue included a fake gunshot but he eventually decided for the hanging - without telling us,` he said.

The actor`s mother, from Como, northern Italy, rejected the theory explored by police that he may have tried to commit suicide.

She said: `My son recently lost his father and had ended a relationship but had found his serenity again.

`He didn`t leave a suicide note and had no reason to kill himself.`

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