Grasping a man by the head, 'Joao de Deus', or John of God, plunges metal forceps deep into his brain. Moments later he withdraws them clutching a rancid yellow tumour. The man had received no anaethetic or pain killers, yet claimed to feel no pain at all. By rights he should be dead. For armies of terminally ill, Joao is a true miracle worker.

Ever since he was 11, when 'a woman in white appeared' to him, Joao has been convinced of his place as God's miracle worker on earth. 'Guided by spirits', Joao set up his house of healing - The Casa de Dom Inacio - in the village of Abadiania in Central Brazil 25 years ago. His fame has spread worldwide. Floods of people have put their faith - and their lives - in his hands.

One man is Miguel. In front of the camera, Joao performs his 'magic'. Seemingly unfazed by the invasive surgery Joao is undertaking on his arm, he conducts a perfectly normal conversation with the filmmaker: 'I don't feel anything. No problem' he smiles.

There is little doubt at least some of John's work defies medical science. Dr. Jeffrey Rodiger of Harvard Medical School is as confused as everyone else: 'If it is true, then it's a world-view destroyer for me because it means there are things happening I don't know how to explain'. The anaesthetic and sterilisation free surgery leaves him wide-eyed in disbelief. 'How is this taking place without infection? How is this taking place without blood loss? And how are people not screaming their heads off?'

But not everyone is a convert. Irishwoman Joan has MS, and for her too, Joao seemed like a saviour. Dressed in white 'because the healer says it helps him see the energy field around them', she made the painful trip several thousand kilometers to Brazil. But whilst she sees what clearly appear to be miracles, for her, John of God can do little to help. She leaves non-plussed and despondent.

But the incredible events captured on film are difficult to displace. For many, there can be no explanation except that God is working through John. The camera captures the moment when Rodiger's last shred of scepticism is removed. Having a stain pointed out by a colleague, he looks down at his shirt. Just below his ribs, where Jesus was speared, is a scarlet stain, slowly spreading outwards. He bleeds for over an hour despite attempts to stem the flow. 'Jeffrey was experiencing what the locals call an invisible physical surgery. People claim that this spontaneous appearance of cuts and bleeding happens quite often outside of the Casa'. It's a clear stigmata, and something science cannot account for.

Some people may be sceptical, others immediately convinced of the power of God. The stark responses of those who made the trip, however, speak for themselves: 'Places like this, they may manifest aspects of the Divine which are not as easy to find elsewhere. But the Divine is everywhere. This is just a special case of what's everywhere I believe.'