The spiritual guru to China's corrupt officials
One of China's most high-profile former officials, Zhou Yongkang, has been sentenced to life imprisonment on bribery charges and for leaking state documents to an individual. This was revealed to be Cao Yongzheng - a 56-year-old qigong master, businessman and mysterious "spiritual adviser" to the elite.
It is not known how Mr Cao personally influenced Zhou, but the two were said to be close, and Mr Cao had profitable business dealings with the state-owned China National Petroleum Corporation (CNPC) which Zhou and his allies headed for decades.
Mr Cao was also connected to Sichuan province's former deputy party boss Li Chuncheng and former CNPC boss Jiang Jiemin.
In Zhou's verdict, the authorities said he requested Mr Li and Mr Jiang to "provide assistance in carrying out business activities" for a number of people - including Mr Cao - who earned 21.4 billion yuan (£2.2bn, $3.45bn) in "illegal profits".
In the mid-2000s, Mr Cao was involved in setting up arms of the China Niandai Energy Investment company across the country.
The company signed lucrative deals with the CNPC to develop oilfields in Jilin province and Shaanxi. In 2005 Mr Cao reportedly paid a billion yuan to buy a building in Beijing and turn it into Niandai's headquarters.
But questions were soon raised about Niandai's huge profits despite little investment and development.
The Chinese authorities began arresting a number of Zhou's allies in 2012, and Niandai later shut down. The company was put under investigation for its dealings with the CNPC, and senior company officials were detained.
Mr Cao first got to know Zhou Yongkang through his eldest son, Zhou Bin, around the year 2000. He quickly won their trust when he began mentoring younger son, Zhou Han.
Zhou Yongkang reportedly boasted Mr Cao was "the person I trust the most".
Mr Cao first made his mark as a master of qigong - a type of spiritual practice linked to exercise - in the 1980s in the western province of Xinjiang.
Dubbed the "Xinjiang sage" for his gifts in spiritual healing and insight, he later moved to Beijing where he attracted the rich and powerful.
In the 1990s, a People's Daily article claimed he could tell a person's future based on a single look at his face, and could heal incurable illnesses with his touch.
Some accounts said he made a barren woman fertile, and managed to predict, a week in advance, that a businessman would suffer from a heart attack just by looking at his name.
Those who met him said he was charismatic and knowledgeable, but strove to maintain a humble appearance.
Yaxin Online reported that when Mr Cao visited his Xinjiang home in 2000, villagers found he had "no airs".
"He dressed normally, wore thick glasses, and didn't at all look like a rich and cultured person. He looked more like a farmer," one resident told the news portal.
The Cultural Revolution and subsequent fast-paced economic development created "a spiritual crisis" in China, said Kerry Brown, director of the Chinese Studies Centre at the University of Sydney.
Superstitions and alternative beliefs have flourished in this vacuum - qigong became a national craze in the 1980s.
On top of that, senior officials inhabit "a lonely place where it is difficult to trust anyone - which is perfect if you're a wily spiritual guru," said Professor Brown.
"On paper, officials are Communist, but privately many don't believe in this ideology. They go to these gurus when they run into problems and need assurance," said sociologist Ding Xueliang of the Hong Kong University of Science and Technology.
Qigong borrows elements from traditional Chinese medicine, "so officials can say they follow it for health, not spiritual, reasons," he added.
Other well-connected gurus include qigong master Wang Lin, a close associate of former railways minister Liu Zhijun who was jailed for corruption; and Zhang Hongbao, the founder of qigong-based group Zhong Gong.
The party leadership closes one eye to such relationships because these beliefs are "not organised like major religions and therefore seen as less dangerous" to the central authorities, said Professor Ding.
But the government has cracked down when these practices were deemed to have crossed the line.
In the 1990s, as such movements became more organised and attracted more followers, the government discouraged "superstitious beliefs". Some, like Falun Gong and Zhong Gong, were branded cults and outlawed.
Wheeling and dealing
Gurus like Mr Cao - who reportedly boasted of knowing 600 officials - also serve as go-betweens among the business and political elite.
One entrepreneur told financial news outlet Caixin that in 2011 he approached Mr Cao for help. One phone call and 30 minutes later, a high-level official was summoned to help the businessman.
"Cao used to say, 'Those guys on the Forbes rich list are not even worth my little finger'," he added.
But Mr Cao's rise was halted with China's corruption crackdown. He was rumoured to have fled to Taiwan and was later detained by the Chinese authorities.
Not much was heard from him until last Thursday, when he resurfaced in Zhou Yongkang's verdict.
It said that Mr Cao had testified against Zhou during a closed trial on 22 May - the first official confirmation that he was in the hands of the authorities.