Nathascha Kampusch, the Austrian kidnap victim, bade farewell to her dead captor in a secret visit to the Vienna mortuary before his coffin was laid to rest in a leafy cemetery in the Austrian capital.

The kidnapper, Wolfgang Priklopil, was buried today under an assumed name in a low-key ceremony attended only by his mother, Waltraud, and a handful of plainclothes detectives.

It has emerged that Frau Kampusch - accompanied by her main therapist, Max Friedrich - entered the Vienna Institute of Forensic Medicine by a backdoor yesterday and spent a few minutes in silent contemplation in front of the coffin containing his remains.

Priklopil threw himself in front of a moving express train only hours after Natascha escaped from his clutches in a dramatic sprint through suburban back gardens on August 23.

The gesture by Frau Kampush was not intended as one of respect for the man who had locked her behind a 150kg steel door for more than eight years. Rather, it was part of her complex therapy.

Prof Friedrich has been searching for ways in which Frau Kampush can separate from the trauma of imprisonment. Her relationship with Priklopil was intense and she has hinted to interviewers that she still feels partly guilty for his death. "I was stronger than him," she said in one interview.

Priklopil had bullied her but ultimately kept her under control by threatening to kill himself. This was a potent threat: had he committed suicide while she was locked in her basement prison, she would have died a slow, lingering death.

Frau Kampush therefore spent much of her energy trying to lift the spirits of her kidnapper and turn his thoughts away from suicide. "Now the killer is dead and she is free but the guilt lingers on," explained a Vienna therapist.

Prof Friedrich has been encouraging Frau Kampush to write a book about herself. "This would certainly have a cathartic element," he said.

It is unclear, however, whether Frau Kampusch kept - as some media scouts believe - a secret diary during her confinement.

Police said today that they were interrupting their questioning of Frau Kampusch to allow her to recover from the flu, symptoms of which were clearly apparent during her television interview on Wednesday night.

Major General Gerhard Lang, head of the Austrian Federal Criminal Agency, says that one priority is to find out whether Priklopil had an accomplice. A 12-year-old girl who saw Priklopil snatch Natascha in 1998 claims also to have seen a second man in the driving seat of the white van that was used as a get-away vehicle. Natascha, however, says that the kidnap was conducted only by Priklopil.

Some clues may come in an excavation of Priklopil’s garden. Helped by an archaeologist, detectives were today trying to discover whether the kidnapper hid and buried evidence under the lawn.

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