The Practical Wisdom group had formed in 2002 as a way of making available to leaders in Australian business, public health, government and defence "authentic Buddhist teachings on meditation, compassion and wisdom" from arguably the most famous Tibetan in the world after the Dalai Lama. Sogyal Rinpoche had first started visiting Australia in the mid-1980s, nearly a decade before his book was to become a spiritual classic. Regarded as a master of the great Tibetan oral traditions, Rinpoche's book had managed to lay out in simple, eloquent terms various Buddhist concepts on impermanence, karma, rebirth, compassion for the dying, and the benefits of training the mind through meditation. In so doing, he slaked a spiritual thirst and inspired millions. Comedian John Cleese described the book as the most important he'd ever read, while the San Francisco Chronicle called it a "magnificent achievement" and an "inestimable gift". Around the world, hospitals, health institutions and palliative care centres began adopting the book as an invaluable aid in dealing with the sick and dying. But on July 14 this year, Rinpoche's world came crashing down, and soon thereafter the faith of thousands of his devotees and admirers. That was the day he received a 12-page letter from the eight former senior students accusing him of years of violent and abusive behaviour. "This letter is our request to you to stop your unethical and immoral behaviour," they wrote. "Your public face is one of wisdom, kindness, humour, warmth and compassion, but your private behaviour, the way you conduct yourself behind the scenes, is deeply disturbing and unsettling."

The letter then laid out in spectacular and shocking detail the nature of the Tibetan master's alleged abuse: "We have received directly from you, and witnessed others receiving, many different forms of physical abuse. You have punched and kicked us, pulled hair, torn ears, as well as hit us and others with various objects such as your back-scratcher, wooden hangers, phones, cups and many other objects that happened to be close at hand." "Your physical abuse – which constitutes a crime under the laws of the lands where you have done these acts – have left monks, nuns and lay students of yours with bloody injuries and permanent scars. This is not second-hand information; we have experienced and witnessed your behaviour for years." Among the letter's co-authors: his Australian IT expert Ngawang Sangye, and his personal assistant, an Australian artist turned Buddhist nun known as Drolma, who fled Rigpa – the organisation Rinpoche founded – in 2010 after what she claims was nearly eight years of abuse. You use your role as a teacher to gain access to young women, and to coerce, intimidate and manipulate them into giving you sexual favours. Excerpt from letter written to Rinpoche from eight former students "His behaviour was often wildly unpredictable and irrational," Drolma tells Good Weekend in a Skype interview from London, where she now lives. "If anything went wrong and his anxiety got the better of him, he would take it out on me. One of those times he grabbed me by the ear and it was torn all the way along the back. There was blood pouring down my neck."

Sogyal Rinpoche lectures to a captivated audience in Sydney in 2011. Credit:Mayu Kanamori According to his accusers, the mistreatment went far beyond the physical. "Your emotional and psychological abuse has been perhaps more damaging than the physical scars you have left on us," they wrote. "You have threatened us and others, saying if we do not follow you absolutely, we will die 'spitting up blood'. You have told us that our loved ones are at risk of ill-health, or have died, because we displeased you in some way." Then came a range of alleged eye-popping sexual misdeeds. "You use your role as a teacher to gain access to young women, and to coerce, intimidate and manipulate them into giving you sexual favours." "Some of us have been subjected to sexual harassment in the form of being told to strip, to show you our genitals (both men and women), to give you oral sex, being groped, asked to give you photos of our genitals, to have sex in your bed with our partners, and to describe to you our sexual relations with our partners." "You have for decades, and continue to have, sexual relationships with a number of your student attendants, some who are married. You have told us to lie on your behalf, to hide your sexual relationships from your other girlfriends. Publicly you claim that your relationships are ordinary, consensual and proper because you are not a monk. You deny any wrongdoing and have claimed on occasion that you were seduced."

The letter was an incendiary device dropped in the heart of one of the world's major religions. It was sent not just to Rinpoche, but also copied to the Dalai Lama, a select group of Tibetan Buddhist teachers, and a number of Rinpoche's senior students. It was leaked almost immediately, going viral on social media and creating the kind of uproar we've become accustomed to seeing lately in Hollywood, or indeed the Catholic Church, but seldom in the serene, do-no-harm world of Buddhism. Here was the spiritual director of a global organisation, Rigpa – the name is a Tibetan word meaning an awareness of the innermost nature of mind – being accused not just of physical, psychological and sexual misconduct, but also of maintaining a "gluttonous" lifestyle that had been funded by – and kept hidden from – his thousands of students for decades. And this from a man who had taught so masterfully on how to find inner peace and contentment. "I have a complex PTSD [post-traumatic stress disorder] that comes from long-term devaluation, neglect and assault," Ngawang Sangye tells Good Weekend. "I was a monk for 14 years and that's why I had very close access and saw things like Sogyal punching women, men, slapping, hitting with objects. There is an element of shame in how long it took me to break [away] because I thought it wasn't as bad as it looked. "It was much worse than it looked. Harvey Weinstein has nothing on this person."

Sogyal Rinpoche was six months old when he entered the monastery of his spiritual master Jamyang Khyentse in the wild, mountainous Kham province of eastern Tibet known as the "Land of Snows". For centuries monasteries had provided Tibetan children with their main source of education, occasionally finding among their young charges the reincarnations of great masters who had passed away. By his own account, Rinpoche was one of these select children. Although born into a family of traders known as the Lakars, he was given the name Sogyal by his master, who recognised him as the incarnation of the great 19th-century visionary saint, Tertön Sogyal, a teacher to the 13th Dalai Lama, predecessor to the current Dalai Lama. At the time of Sogyal Lakar's birth in 1947, Tibet was under the nominal protection of India, but soon to become one of the world's most troubled countries following the Chinese invasion in 1950. In 1954, Sogyal escaped with his family over the mountains to India, five years before the Dalai Lama fled the country and more than a decade before the full horrors of the Chinese genocide began to reveal themselves. As American author John Avedon describes in his celebrated book, In Exile from the Land of Snows: "The obliteration of entire [Tibetan] villages was compounded by hundreds of public executions, carried out to intimidate the surviving population. The methods employed included crucifixion, dismemberment, vivisection, beheading, burying, burning and scalding alive, dragging the victims to death behind galloping horses and pushing them from airplanes; children were forced to shoot their parents, disciples their religious teachers. Everywhere monasteries were prime targets. Monks were compelled to publicly copulate with nuns and desecrate sacred images before being sent to a growing string of labour camps." Like all Tibetans of his generation, Sogyal Lakar almost certainly carried the traumas of his ravaged country into exile. After being schooled in India and attending university in Delhi, he arrived in London in the early 1970s to study comparative religion at Cambridge University's Trinity College. He soon assumed the honorific of Rinpoche (meaning "Precious One") and began establishing himself as a teacher, finding a receptive audience among young Westerners searching for the kind of spiritual enlightenment Buddhism seemed to offer.

Sogyal Rinpoche became a Buddhist superstar after the release of his book, which has sold more than 3 million copies worldwide. Credit:Mayu Kanamori MKZ Buddhism's appeals were manifold. It taught that true happiness could never be achieved while humans were governed by negative emotions such as attachment, pride, jealousy, hatred and ignorance. This ignorance related to the ego's perception that reality was solid and permanent when – according to Buddhist precepts – the opposite was true. Everything was impermanent – thoughts, feelings, judgements, opinions, life itself – and it was only through training the mind that the true nature of reality could be discovered and suffering ended. Buddhism had first come to Tibet in the seventh century as a complex philosophical and ritual system known as Vajrayana Buddhism. This form of Buddhism emphasised transforming the mind through "skilful methods"; and this was what Sogyal studied from childhood. Vajrayana Buddhism was no easy path. In order to slip the shackles of the ego, a student needed to give total obedience to the teacher, no matter how unreasonable or irrational the teacher's behaviour might seem. "Crazy Wisdom" was the name given to this form of instruction, where a guru could employ all sorts of outlandish methods to challenge a student's ego. Tibetan Buddhism is filled with such stories and Sogyal Rinpoche cited a perfect example of one in The Tibetan Book of Living and Dying. He described how a Tibetan master, Patrul Rinpoche, was introduced to the nature of mind by being knocked unconscious by his own master, Do Khyentse:

"As Patrul Rinpoche approached, prostrating all the time, Do Khyentse hurled pebbles and then larger rocks and stones at him. When he finally came within reach, Do Khyentse started punching him and knocked him out altogether." "When Patrul Rinpoche came to, he was in an entirely different state of consciousness. Each of Do Khyentse's curses and insults had destroyed the last remnants of Patrul Rinpoche's ordinary conceptual mind, and each stone that hit him opened up the energy centres and subtle channels in his body." In Sogyal Rinpoche's case, the "channels in his body" were less than subtle, according to British journalist Mary Finnigan, who was to spend nearly two decades trying to expose him. "I'm one of the people who launched Sogyal on his career as a teacher in London in 1973, when he was very young and very inexperienced," she told a Canadian documentary team in 2011. "There was just this continuous stream of seductions. He didn't even hide it in those days. He was absolutely flagrantly promiscuous. He would pick girls up – usually vulnerable, needy – and entertain them for a short while and then dump them." One of those young women, American Victoria Barlow, first met Rinpoche in New York in 1976 after grappling for years with her own childhood sexual abuse. Rinpoche was visiting Chogyam Trungpa Rinpoche, the pioneer of Tibetan Buddhism in the US, and Barlow wanted Sogyal Rinpoche's advice on the dharma, or Buddhist teachings. "He opened the apartment door without a shirt, holding a bottle of beer," Barlow recalls now in a written response to Good Weekend. "I [had] just turned 22 and I arrived in an almost floor-length dark brown tent dress that I had made a few months before in Calcutta.

"I thanked him for taking the time to see me and was in the process of asking him my question when he reached over and touched my cheek. He said, 'I think we have a special connection.'" "My face flushed. I had just been touched by a lama. This was such a blessing … but as I spoke, he reached toward me and literally mashed my face with his face. He was literally slobbering all over me. "He roughly put his hand up my long dress, groped my privates, unzipped himself and lay on top of me, literally grunting for the minute or two until he released. Immediately, he got up, said he had things to do, that he was getting ready to travel across America." Barlow was mortified, but still willing to believe that – in the spirit of "Crazy Wisdom" – Rinpoche had just transmitted a powerful "source of enlightenment". In the following months, she received several calls from him, including one from Trungpa's spiritual centre in Boulder, Colorado, where Rinpoche "spoke with amazement about how Trungpa had girls lined up outside his door like a rock star and that he wanted that, too. I thought he was joking and only later realised that was his actual aspiration, to have a conveyor belt of groupies."

Despite growing doubts, Barlow allowed her spiritual mentor to convince her to fly to Berkeley, California to receive teachings from another Buddhist master. She was invited to stay with an American couple, both Tibetan Buddhist students who showed her a room with two beds. "They said, 'That's Sogyal's bed next to yours. He told [us] to put you in here.' I felt a combination of shock, shame, humiliation, defeat and anger." "Within a minute of his arriving in the room, Sogyal said he'd had a fight with his girlfriend in London. He made it apparent that he wanted sex with me, so that made me just some lay he'd arranged to use in Berkeley." Barlow concluded then that Rinpoche was a "charlatan"; that she needed to get away as soon as possible. "Eight weeks later," she says, "I miscarried his child." The Tibetan Book of Living and Dying became a spiritual cause célèbre almost from the moment it was published, eventually selling more than three million copies worldwide and being translated into 34 languages in 80 countries. In a world dominated by greed, cynicism and personal grandstanding, the 1992 book presented a compelling philosophy for modern life, drawing deeply from ancient Buddhist teachings. Rinpoche was suddenly a Buddhist superstar, soon appearing in Bernardo Bertolucci's 1993 film Little Buddha, and travelling the world establishing new centres for Rigpa, the organisation he'd set up under the patronage of the Dalai Lama. After starting out in a London squat in the early 1970s, he was on his way to building a global organisation with 130 centres in 41 countries, including Australia, relying mainly on the generous donations of his growing legion of students.

In 2007, the then Irish president Mary McAleese opened his spiritual care centre in south-west Ireland. The following year the Dalai Lama, together with France's first lady at the time, Carla Bruni-Sarkozy, attended the inauguration of his $12 million temple, named Lerab Ling, in Roqueredonde in southern France. Sogyal Rinpoche (right) in 2008 with the Dalai Lama and Carla Bruni-Sarkozy. Credit:AFP Through his efforts, millions of people were becoming exposed to the wise and gentle teachings of Buddhism; hospitals, palliative care centres and healthcare practitioners were beginning to adopt Buddhist methods in tending to the dying and their families; international conferences were being held on ways of creating more compassionate societies. "Mindfulness" was becoming the new buzzword, in no small thanks to this Tibetan son of traders. In 1989, Rigpa established itself in Australia, with hundreds of people flocking to the first of its annual retreats on the shores of Myall Lakes, north of Sydney. (Rigpa would later spend more than $1 million having a Glenn Murcutt-designed home built for Rinpoche at nearby Blueys Beach.)

The Tibetan lama's appeal was self-evident. Not only did he have a great command of English and a mischievous sense of humour, his teachings were lucid and accessible. "If you really know how to take the teachings to heart, happiness is in ourselves," he told his rapt audience during one retreat. "It's the way we think. And there we can think of what Buddha said: 'We are what we think, all that we are arises with our thoughts. With our thoughts we make the world.' " For the purposes of disclosure, I attended a few of his retreats in the early 2000s. I wanted to learn how to meditate, but also to understand better how Buddhism could be integrated into modern life. In 2001, I reported on a historic meeting at the Commonwealth Bank's Sydney headquarters where 200 Australian business leaders – chief executives, bankers, brokers, management consultants, investment advisers and fund managers – met with Rinpoche to explore ways of bringing "wisdom" and "compassion" into their businesses. Two days later, the Tibetan teacher spoke to leaders of the future at the Australian Graduate School of Management about "values-based leadership". Rinpoche had been urged to do so by Ian Buchanan, one of Australia's leading management consultants, who, in turn, had been asked to become involved by Sue Pieters-Hawke, the eldest child of former prime minister Bob Hawke and his wife Hazel. Both Buchanan and Pieters-Hawke were students of Tibetan Buddhism. Buchanan had been introduced to The Tibetan Book of Living and Dying nearly a decade earlier after being told he was dying from an incurable illness. (He underwent three years of treatment for what he describes as "a cross between tuberculosis and leprosy".) Based in Singapore, Buchanan flew to Sydney to attend a Myall Lakes retreat and then, after, relocating to Sydney in 2000, visited the retreat on a regular basis to receive more of Rinpoche's teachings. The two men developed an instant rapport.

"I'd been advising government and business for many years," he explains now, "and so I started to talk to Rinpoche about what I thought was a desperate need of business leaders to get into meditation, given that they had few ways of letting go of their stress. Rinpoche said, 'I don't know anything about business. Will you teach me?' And so we pulled together a small group and we became his business coaches." From this initiative, the "Practical Wisdom" leaders' retreat was born in 2002. It was the business offshoot to Rigpa and, uniquely, it involved a select group of Australian business figures meeting annually with the Tibetan teacher to learn how to apply Buddhist principles to their personal and professional lives. Gordon Cairns, currently the chairman of both Origin Energy and Woolworths, became one of the organisers while serving as chief executive of Lion Nathan Breweries. He'd just finished reading The Tibetan Book of Living and Dying and was attracted to its themes of interconnectedness and the requirements of acting with compassion. "I've always believed we have to find the answers to the big questions: Why are we here? and What's the meaning of life?" he tells Good Weekend. "It was more than running a beer company or being the chairman of Woolies. To me it was the whole [Buddhist] principle of bodhicitta – which is loving-kindness. "I think [these teachings] helped me change in ways for the better: from being a tough perfectionist, internally competitive, nothing-is-ever-good-enough chief executive, to one who is humanistic, encouraging, inspiring."

Over the 15 years that Buchanan and Cairns helped convene the "Practical Wisdom" retreats, there was nothing in Rinpoche's behaviour to suggest scandal. Yes, there had often been questions about his inner circle of beautiful young women, and how it was that a teacher of loving-kindness could so often publicly humiliate his senior students. But never a hint of physical or sexual abuse. According to Drolma, his former personal assistant, that was because the abuse only ever happened behind closed doors. "Sometimes he would just lay into me in the stomach and I'd be winded and he'd bring me to tears," she recalls now. "Then he would sometimes follow up with a slap … but I had to help him put on his ceremonial robes and get ready to put him on stage with all the other Tibetan lamas and monks. Sogyal would then walk on and be part of the ceremony and I would have to follow him, holding his ritual objects, with tears streaming down my face. Nobody else had seen it. "I'd always thought it was due to my imperfections, that this was my fast-track to enlightenment … but when the humiliation and abuse didn't stop, that's when I started thinking, 'This is just an abusive man, it's not an enlightened person working on my spiritual wellbeing.' " Barbara Lepani, a senior policy officer with the federal Department of Communications and the Arts, poses a different view. As a senior student of Rinpoche for nearly 35 years, she knows what it's like to be on the receiving end of his "crazy wisdom". She remembers once being whacked over the head with a wooden umbrella after failing to distil his teachings. "My first reaction was anger: 'How dare you?' But then the story of Do Khyentse knocking Patrul Rinpoche unconscious came to mind, and I thought, 'Hang on, is this what's going on here?' Because Rinpoche didn't do such things with just anyone. He always checked to see whether you were 'with him' and could take him on as a Vajrayana master."

This was the point that another Buddhist master, the filmmaker and writer Dzongsar Khyentse Rinpoche, tried to make recently after being asked to comment on the scandal. "Frankly," he said, "for a student of Sogyal Rinpoche who has consciously received abhisheka [initiation into any Vajrayana teaching] – and therefore stepped onto the Vajrayana path – to think of labelling Sogyal Rinpoche's actions as 'abusive', or to criticise a Vajrayana master even privately, let alone publicly and in print, or simply to reveal that such methods exist, is a breakage of samaya [the sacred spiritual bond between student and teacher]. "[But] if no proper warnings and no fundamental training were given prior to the Vajrayana teachings, then Sogyal Rinpoche is even more in the wrong than his critical students." Dzongsar Khyentse seemed to be having a bet each way. He also expressed puzzlement that "intelligent" students hadn't better analysed their teacher before signing up. "I really don't understand why they waited 10 or even 30 years before saying anything. How come they didn't see all these problems in the first or second year of their relationship with Sogyal?" For those who wanted to look, the signs had been on the public record for more than two decades. In 1994, an American student – using the pseudonym Janice Doe – filed a lawsuit in the Superior Court of California seeking $US10 million in reparations from Rinpoche for sexually and physically abusing her. The case was settled out of court and, in those pre-internet days, the matter quietly faded, although not without a number of outraged devotees deserting ship. The following year, the UK's Telegraph magazine published new allegations of sexual abuse by two more women. In 2011, a Canadian documentary In the Name of Enlightenment aired, with Victoria Barlow going public, as well as a young Frenchwoman, "Mimi", who described years of Stockholm Syndrome-like abuse. "You are locked up in this tiny environment," she said, "where someone is beating you up every day, but he's also the person who's giving you [your] only emotional attention."

The dam finally burst last year at Lerab Ling in France, when Rinpoche punched Ani Chökyi, a Danish nun, in the stomach in front of 1000 students. Ani Chökyi later issued a statement insisting that Rinpoche had been "loving beyond any ordinary description" and that the blow was a "soft punch". Not according to Gary Goldman, a former US army ranger and long-term Buddhism student seated up the front. "I guess the footstool wasn't in exactly the right position," he told the UK Telegraph. "He had this flash of anger and he just punched her – a short gut punch." That was enough for Goldman to leave Rigpa and put his name to the letter accusing Rinpoche of abuse. Four days after receiving their letter, Rinpoche replied, expressing his sadness and distress, but claiming his conscience was clear. "From the bottom of my heart I humbly ask your forgiveness," he wrote. "Since reading your letter I have been thrown into deep reflection and I'm finally resolved that if this is the way that my actions are perceived, then I do need to take real action. If I am the problem, that can be solved. There's no need to bring everything down. I implore you to keep this bigger picture in mind." Less than four weeks later – on August 11 – Rinpoche announced his decision to retire as spiritual director of Rigpa, while also reaffirming his decision to enter a three-year retreat. That same day, the international Rigpa board announced the establishment of an independent investigation by a "neutral third party" and a new "code of conduct and grievance process".

The Dalai Lama himself made it clear he was in no mood for equivocation. At a Buddhist seminar in northern India's Ladakh, he declared emphatically – and not for the first time – that ethical misconduct was often caused by Tibet's traditional feudal system and that students should never follow their guru unquestioningly. He then said his "very good friend Sogyal Rinpoche" was "disgraced" and he encouraged all such misconduct to be made public. It was a devastating rebuke from Buddhism's most revered figure. While no charges had been laid at the time of writing, a number of complaints have reportedly been filed with police in various countries, including France and England, and the Charity Commission in the UK has begun a preliminary investigation. Sogyal Rinpoche has also been diagnosed with colon cancer and undergone surgery on two tumours. On that late September evening in the Sydney boardroom of Port Jackson and Partners, 10 weeks after the abuse allegations were first made public, 22 business leaders convened to vent feelings ranging from "shock and anger to dismay and confusion". Some were so visibly moved, they cried. As Ian Buchanan recalls now: "A number of them said, 'I will never be able to watch the videos of him teaching again.' And I said, 'Well, I will.' It's not that he might not have let us down very badly, but the teachings and the way he teaches them are invaluable and precious, and for me have been of incalculable value in having a relatively peaceful, stable life in the face of some near-death experiences."

While not defending the alleged abuses, Buchanan voices his sorrow at Rinpoche's stunning fall from grace – a man who has given his life to bringing Buddhism to the West after fleeing his country as a child refugee. "He's done a wonderful job of sharing the teachings, but that does not preclude him having that damage as a human being." Jillian Broadbent, a former member of the Reserve Bank board and currently chancellor of the University of Wollongong, agrees with Buchanan. "I have found the teachings of mindfulness most valuable, both in difficult times and in my daily living," she tells Good Weekend. "They have similarly brought value and contentment to many others for more than two millennia. I certainly see merit and increased effectiveness in a wider adoption of Buddhist ethics across the Australian business community. I am aware of the allegations against Sogyal Rinpoche [but] I remain appreciative of my own learnings and benefit from the teachings, and respectful of their long lineage. It would be really disappointing if these allegations damaged the teachings and the benefits their adoption can bring." Gordon Cairns echoes these sentiments, acknowledging how deeply he has been influenced by Buddhism and how important it is now not to conflate the teachings with the teacher. At the same time, he urges his colleagues to separate from Rigpa and find another Buddhist master (a position the group has since adopted). "This teaching has had a wonderfully profound effect on the West," he tells Good Weekend. "It's had a wonderfully profound effect on business leaders here in Australia, and a wonderfully profound effect on me."

The chairman of Woolworths then offers a Buddhist parable to sum up his sympathy, not just for Rinpoche's alleged victims but for Rinpoche himself: "When you see a man beating a dog, you feel as sorry for the man as you do for the dog." In a perfect world, that is a wonderful testament to forgiveness, but for Sogyal Rinpoche's strongest critics, perhaps not in this lifetime.