About 10 minutes' walk outside the village, on a small wooded hillock guarded by armed sentries, is the spartan clinic where cardiac surgeon Jonathan Ho Kei-shing is alleged to have helped perform an operation which has shocked the world: the transplant of a pig's heart and abdominal organs to a man.

It was a startling and unsuccessful piece of surgery. The repercussions are rocking medical reputations from Asia to Europe.

At a time when top British scientists have deemed animal transplants - even those from genetically engineered pigs - too risky, medical experts have expressed disbelief that such an operation could have been attempted at a tiny, poorly staffed clinic in the furthest reaches of India.

The patient, a 32-year-old unmarried farmer named Purna Saikia, who was born with two holes in his heart, came from a remote village more than 300 kilometres from Gawahati. He died shortly after the operation.

The clinic was run by Indian doctor Dhani Ram Baruah and his colleague Dr C S James. But 42-year-old Ho, a long-time friend of Baruah's and a former senior staff member of the Chinese University in Hong Kong, has confirmed to the South China Morning Post his part in the transplant operation.

All three were arrested soon after Saikia's death and have spent more than a month in Gawahati district jail seeking bail. They are charged with manslaughter and violation of India's transplant laws.

The controversy began in mid-December when Baruah, an Assamese doctor who has acquired a reputation for medical entrepreneurship with an eye for commercial profit, announced he had successfully performed the world's first pig-to-man heart transplant at his Sonapur clinic.

Baruah spent months courting local media with tales of his impending surgical breakthrough, but it was only when he named the patient and declared the operation had taken place that the case began to take on greater importance. Press photographers who claim Baruah invited them into the operating theatre to document the December 15 procedure have produced photographs of both pig and man on operating tables, attended by masked surgeons. The event - and Baruah's subsequent announcement of Saikia's death on January 7 - caused consternation in Gawahati and beyond.

Gawahati Medical College Hospital's chief superintendent Dr A K Baruah, not related to the jailed doctor, articulated the medical community's growing suspicions about the type of research carried out in the shuttered and guarded Baruah Heart City.

'People were suspicious,' he said. 'The problem was that they did everything in a secluded place where no one was allowed in. If they were doing a good thing for the first time in the world, why not take the medical establishment into their confidence? Some people say the whole thing was a hoax. Others say it was a medical experiment.' Assam's joint director of health services Ramesh Barma set out on the bone-jarring one-hour drive from Gawahati to Sonapur twice - the second time with a police escort - before Baruah's guards would allow him to see their master.

'On December 15, he published that he had transplanted the pig's heart into the man,' Dr Barma said.

'On the 18th I went out there, but he did not allow me to see him. Then again on the 20th I took police and entered his premises, but he denied he had done the transplant. He said he had not done anything, only repaired the heart with a patch.' Dr Barma was allowed to see Purna Saikia, who lay swathed from neck to groin in bandages. 'He was not so well,' he said.

'Then on January 8 in the local daily news, it came out that the patient had died on the seventh and the government asked me to investigate about the pig.' The following day, Dr Barma returned to Baruah Heart City, a single-level structure resembling a prefabricated building-site office, accompanied by a cardiologist, a thoracic surgeon, an anaesthetist and a magistrate.

'When I saw the dead body on the ninth, there was a big incision from the throat down,' he recalled.

'I inquired where were the organs that had been removed. Baruah said he had preserved them. In the morning he told me he had [only] done the heart, lung and kidney. But by 3pm I had seen the liver, pancreas, everything.' Dr Barma said that Baruah had admitted carrying out a second operation on January 4, three days before Saikia died. The man's abdominal organs had become infected after the first round of surgery, so Baruah and Ho had operated again to remove the infected components. 'He transferred the pig's organs to the patient,' Dr Barma said. 'He said, 'I have done it'.

'I inquired who had done the anaesthetic on the pig and Baruah told me he had. He told me he had also done the anaesthetic on the man.' That evening, Baruah, Ho and James were arrested and taken by police through the teeming, dusty streets to the jail, where a set of dilapidated gallows bear witness to India's colonial past.

What induced former Chinese University chief of cardiothoracic surgery Jonathan Ho to make his way across Asia to the village of Sonapur - and later to the dank cells of Gawahati jail - may be known fully to only two men: Ho and Baruah.

In 1992 Ho, a United States-trained surgeon, was heading a programme at the Chinese University and Prince of Wales Hospital which fitted patients with a new type of heart valve. Instead of being mechanical, they were fashioned from Indian ox tissue and promoted by Baruah as the 'Baruah valve'. The programme initially was known only to a select few at the university, but it came under heavy criticism when news of its existence emerged.

On May 1, 1992, Ho and his team called a press conference to announce that the valves had been substituted for standard artificial devices and 'successfully' fitted to 10 Prince of Wales patients.

But an internal investigation, headed by senior lecturer John Sanderson, later revealed 12 patients had received the experimental valve, six of whom had died - two even before the press conference was called. It also emerged that Baruah had offered his valves to cardiac surgeons at Grantham Hospital but was turned down.

Despite the programme's demise amid a row which split the medical community, Baruah and Ho kept in touch. Ho is understood to have reintroduced ox tissue valves in late 1993.

Finally last December, after Baruah and Ho spoke by telephone about work to be done in the Sonapur clinic, Ho suddenly resigned his position at Chinese University and flew to Gawahati.

It's a city Mrs Ho Chu Yin has come to know well as she trudges daily from her guesthouse along muddy roads to the gates of the prison to bring her jailed husband lunch and religious literature.

'There was no official invitation,' she said. 'Dr Baruah was doing some research, that's what I understand. Jonathan was invited here as a consultant to the clinic, just for a week or so . . . and to do some research.

'He was in touch with Dr Baruah, but I don't think he was working with him as such because he was still in full employment at Chinese University. He still had a few months to go - up until the middle of April.' But the December visit was not the first time Ho had driven up to the bamboo boom-gate of the centre, grandly advertised on a large billboard as Dr Dhani Ram Baruah Heart Institute and Research Centre - Baruah Heart City.

It's a name known thousands of kilometres from Assam, in the German city of Stolberg where a medical equipment company is moving at a furious pace to distance itself from an international scandal brewing over the pig heart affair.

Representatives of the medical technology firm Medos recalled meeting Ho and Baruah in discussions over its sponsorship of Baruah Heart City, while Ho was still working at Chinese University. 'Dr Ho was introduced by Dr Baruah,' said company secretary Ilke Zand. 'He was there when the clinic was officially opened in 1995.

'After that we met him at a congress in Paris. Dr Baruah mentioned Dr Ho was going to help him with the operations, just as we have sent teams down from Germany.' Baruah convinced Medos to come up with the 1.5 million marks (about HK$6.9 million) which funded Heart City.

Business and technical director Rolf Eilers said the ill-fated relationship began when Baruah offered Medos the production rights to his ox tissue valves.

'Medos was interested in the heart valve he had developed,' Mr Eilers said. 'We had done a lot of tests in Germany and it looked good.

'I never knew whether Baruah had developed the valve or whether it was one of his employees, but it was called the Baruah heart valve. The relationship started this way, then he came to us with plans for the hospital. It was in the range of US$1 million [HK$7.73 million]. Up until a certain point we supported him, and we were interested enough to build the clinic for him in India because there is a lot of demand in this field.' German and Russian medical technologists visited Sonapur to help install the medical machinery, but in less than a year the relationship had soured.

Ms Zand said Medos became increasingly anxious about Baruah's surgical knowledge and was being kept in the dark about where its funds were being funnelled: 'We wanted to put our products on the market . . . we made sure we sent all the machinery, but there were problems with customs. We couldn't tell where the money was going.' She said Medos sent people to help Baruah start operating the clinic. 'In the beginning they were saying there were a lot of patients who needed help,' Ms Zand said. 'The machinery was of the highest standards but the hygiene standards left a lot to be desired. We could in no way guarantee that we could do good operations. A heart operation is not an easy thing.' Medos went to the Indian Embassy with its concerns, including a suspicion that the clinic was not a registered hospital - there has been no reply.

Then in August last year, it cut all ties with Baruah. 'In the end we had the feeling we were being lied to,' Ms Zand said. 'As a company, when you feel things are not going the way they should, you withdraw.' In a letter to the Indian Government, Medos says it intends to 'retreat from the whole spectacle'.

Back in Gawahati, framed portraits of Gandhi gaze down on the courtrooms where one judge has refused to handle the pig heart case and two more have complained they cannot read evidence presented against Ho and Baruah in the Assamese language.

Ho's bail application has already stretched out more than a week, interrupted by strikes called by separatist guerillas and a lack of information.

His lawyer, human rights specialist Niloy Dutta, says Ho, Baruah and James could serve up to three years if found guilty of breaching transplant laws. But manslaughter could see Ho serve life.

Saikia's autopsy has been completed by a team of cardiologists, cardiac surgeons, pathologists, police forensic doctors and four vets. But many of the organs and tissues have been sent for DNA testing at a Hyderabad laboratory, and could take some time to return.

'They have to determine two things,' said Dr A K Baruah, whose College Hospital staff took part in the autopsy.

'Which species were the organs that were transplanted and whether the organs which were removed [and preserved] were from the dead body or another person.

'I don't think this has happened anywhere in India - it is unique in the world.'