Today, after 200 arrests, the confiscation of tons of poisonous chemicals in almost daily raids on Aum offices, and the biggest police operation in Japan's peace-time history, they seem to have found him - in exactly the same place.
The sarin case is one of those running sensations so absorbing that it is hard to imagine what Japan - certainly Japanese journalists - will talk about when it is over. Theories about the gas, the sect and its guru have become to Japan what the OJ Simpson trial is to America: a source of dismay and irritation, but an inexhaustible subject for gossip and amateur detective work. "It's a terrible thing about this gas," said a friend's mother who is house-bound and a great watcher of television. "But when it's over, my life will feel so empty."
One report told of a wanted cult follower who underwent plastic surgery, donned women's clothes and had the flesh of his fingertips sliced off to avoid identification. The chief Aum spokesman, a handsome young man named Fumihiro Joyu, became an overnight heart throb with his own following of young women. Shoko Asahara, who disappeared at the time of the attack, was variously said to be in a hotel in Tokyo, a cottage in the Japan Alps, and in Moscow, Colombo or Taipei. The wildest account, narrated by a respected Japanese journalist who has been watching Aum for almost a year, had the guru on a tropical Japanese island in the South China Sea, waiting for a Russian submarine to whisk him off to North Korea.
Japanese have given up wondering whether Aum Shinri Kyo was involved in the sarin attack, but many questions remain. What is Aum Shinri Kyo? By killing 12 people, what did it hope to achieve?
Even by the most extreme standards - Jim Jones, whose followers killed themselves in Jonestown, Guyana; or David Koresh's Branch Davidian sect - Aum Shinri Kyo is an extremely unusual cult. The initial picture of hippy misfits led by a roly-poly Buddha in pyjamas has turned out to be misleading. In structure, the sect is more feudal than communal, with a congregation of ordinary followers led by an lite of "priests".
Certainly it is an organisation of outsiders. The cult claims a Japanese membership of 10,000 and the majority, almost certainly oblivious to the goings-on in the cult's gas-making laboratories, are young, goofy and vulnerable, the kind of students who often suffer horrible bullying in Japanese schools. The sect also has its share of older followers - many of them women - whose "donations" seem to have provided Aum with its immense funds. Japan has hundreds of "new religions" which bring spiritual solace to this emotional underclass. Much of Aum's teaching is no more sinister than that of the Salvation Army: a fusion of Buddhism and Hinduism, stressing meditation, and the promise of salvation based on single-minded reverence of Master Asahara. The cult sells its members "brain-wave" head-gear, made of wires and bandages, which links the teachers' thoughts to their own.
The brilliance of Asahara is the way he appealed to a quite different type of Japanese, equally frustrated in its own way. For all its teachings about meditation and inner ecstasy, Aum seems to have held no appeal to the traditional adherents of Buddhist religion - artists, writers and musicians. The Aum "priests" who have been arrested over the past few weeks, the ringleaders who designed the laboratories, bought the chemicals and, almost certainly, made the sarin, have been young scientists, professionals and technicians, graduates of the finest universities. Joyu, the adored chief spokesman, used to work for Japan's space agency. Another member was one of the country's leading lawyers. One of the key participants in the subway attack was a serving sergeant in the Self-Defence Forces, Japan's army.
To these, the cult delivered a different message: not simply that they would be saved from the imminent apocalypse, but that afterwards they would enjoy power. It is no mere childishness that the cult is organised into a series of "ministries", based on those of the Japanese government. After the predicted global war in 1997, Asahara claimed, it would be the sect's responsibility not only to spread enlightenment but also to take power. For this they would need survivors and tools: chemicals for fertiliser and insecticide, and also, it now seems certain, for defence against the government, which inevitably would try to thwart them.
For these men, all with bright futures at the heart of the Japanese establishment, Aum Shinri Kyo offered not an escape from isolation but an alternative, far more exciting, to a life of conventional achievement. After 15 years of high flying, an employee in a typical Japanese company might become a divisional chief, so long as those higher on the ladder retired or disgraced themselves at the right time. Aum Shinri Kyo organised itself, not as a company, but as a government, with "ministries" of finance, science and defence. Yoshihiro Inoue, who was arrrested yesterday with explosives, drugs and chemicals in his car, was "chief of covert operations" at the age of 25.
It is this cocktail of hard science, tight organisation and, above all, arrogant ambition that make the sect unique. If there is a foreign parallel, it is not with the Branch Davidians but the Michigan Militia. Aum, if anything, commanded even more professional expertise: more than 50 present or former members of the Self Defence Forces, including helicopter and tank specialists, are said to have been members of the cult. They formed a special unit dedicated, according to police, to military overthrow of the Japanese state.
Yesterday's arrests are just the beginning of a long unravelling. The apocalypse may have to be postponed, but no one need worry about the Aum Shinri Kyo roadshow coming to an end for a long time yet.