Kuala Lumpur -- Mr Zabidi Mohamed is an author and a former court magistrate. But he was previously better known as the man who was a fanatical senior leader of a religious cult for 18 years.
The cult itself had a following that extended into South-east Asia - in Singapore, Thailand and Indonesia.
Mr Zabidi was detained under a security law when police swooped on the mystical Al-Arqam group in 1994.
But today, he is a reformed man who is warning people against blind faith and offering suggestions on how to counter the extremist threat from militant groups.
When the 41-year-old speaks about the dangers of giving one's all to charismatic leaders who claim divine sanction, he is talking from experience.
'Before the followers of a group turn fanatical, they are guided into believing the cause by charismatic leaders with sweet promises,' he said in an interview.
Al-Maunah, led by Mohamed Amin Razali. Few had heard of Maunah until July 2000, when 15 of its members led by Amin stole weapons from two army bases in Perak.
They hid in the jungles of Perak and killed two security officers before surrendering four days later.
Mr Zabidi was a lawyer to three members. But he later exposed the group in a book.
Al-Arqam, led by Asaari Muhammad. It was the biggest deviationist group to be uncovered in the region and was banned in 1994 after Asaari claimed the group's deceased founder would return as the Messiah.
The group's membership was said to number 10,000 at its peak in the 1980s.
'People want shortcuts to becoming good Muslims, just like they want to become instant millionaires. So groups like Al-Qaeda exploit this weakness by saying the fastest way to heaven is through its jihad,' he said.
Mr Zabidi was the legal adviser of Arqam, whose chief Asaari Muhammad claimed to regularly receive instructions from Prophet Muhammad in dreams.
Thousands of his followers believed this.
The group attracted attention, because many Malay professionals became its members, and controversy as its teachings persuaded members to run away from home if their families would not accept its teachings.
Many members gave up secure jobs to live in Arqam communes across the country, working for a pittance while running Asaari's businesses. These included small factories, provision shops, schools and clinics.
Asaari today lives in banishment on Labuan island, under police supervision, and the group has broken up.
Mr Zabidi became a turncoat when he realised that Asaari's claims contradicted Islamic teachings, and he began to write about the dangers of the cult.
'Some people were angry with me for writing the book. But I regretted what I had done in the past, so I wrote it as a way to cleanse my sins,' he said.
The father of 11 has also returned to his law practice.
His first book, Tersungkur di Pintu Syurga (Sprawled at Heaven's Gate), was published in 1998. It sold 40,000 copies - a rare feat for a local non-fiction book, where selling 5,000 copies is a big achievement.
The book exposed Asaari as a fraud and called on former members to return to Islam.
Mr Zabidi's second book on the Anwar Ibrahim issue did not do that well, but his third book could be another winner as it has sold 7,000 copies in the past five months alone, he said.
Titled Maunah, Kebenaran Yang Sebenar (Maunah, The Naked Truth), it reveals the untold story behind a militant group that shook the government.
Few people had heard of the Al-Maunah cult until 2000, when 15 of its members led by its chief, Mohamed Amin Razali, stole a cache of weapons from two army bases in Perak.
Amin taught a mystical brand of Islam. A self-proclaimed 'Mahaguru', Amin asked then prime minister Tun Dr Mahathir Mohamad to resign to pave the way for an Islamic administration.
Amin and his gang have since been dealt with in the courts, and given death or life sentences.
Said Mr Zabidi: 'It can be seen from these incidents that while intelligence work might uncover obvious militant groups like Al-Qaeda, the groups that follow the mystical school of Islam could do more damage when they strike.'
In the same vein, he said, members of fanatical groups like Jemaah Islamiah could be reformed if its senior members were first reformed.
Mr Zabidi did exactly just that when he and a few other senior Arqam leaders helped Malaysian religious officials to reform the others.
'It takes a thief to know a thief. I know their lingo and their concerns,' he said.
Muslims must be wary about blindly following only one religious teacher, he said.
'Mix around and never say: this is the leader that brought me back to Islam, so he is my only guide. That is the way to disaster.'