Fumihiro Joyu was the final top official of the Aum Shinri Kyo, or Supreme Truth cult, put into custody.
Two hours before a helmeted Mr Joyu was led out of the cult headquarters by police in riot gear, an unidentified man fired what were reported as blank shots at the building. The man, who appeared to be in his mid- 20s, was quickly surrounded by police, surrendered peacefully and was whisked away in an armoured van.
The arrest came just three weeks before Shoko Asahara, guru of the religious cult, is due to appear in court on multiple murder charges, including the sarin nerve-gas attack which killed 12 commuters on the Tokyo subway in March.
Like the Simpson trial in the US, the Aum affair has become a national obsession. But while OJ Simpson was pursued, arrested and tried under the glare of TV lights, the fate of Mr Asahara and his followers is largely being determined behind closed doors, amid contradictory statements about the guru and the plea he may submit.
Since his dramatic dawn arrest in May, Mr Asahara has been interrogated continuously about a string of grisly crimes attributed to the sect, including the subway gassing, an earlier sarin attack which killed seven people in a mountain town last year, and the murder of a lawyer and his family, whose dismembered remains were uncovered last month. Tons of dangerous chemicals and guns have been recovered from the Aum commune on the slopes of Mount Fuji, and dozens of his followers have implicated him in the crimes. Few Japanese doubt that he was intimately involved in the planning and execution of the murders.
Thirty senior cult members have confessed to a part in the various killings and 50 others face lesser charges, from libel to illegal gun-making. But until now, at least, the guru himself has denied everything.
That seemed to change this week, when Japan's public television network announced that Mr Asahara had confessed to all charges. The report was denied, not only by cult spokesmen, but by the National Police Agency. Then Mr Asahara's lawyer said his client had admitted to some, but not all of the charges.
"I thought I could prevent the sect's disbandment by admitting to ordering or agreeing to the acts," Mr Asahara was quoted as saying. "The sect's teachings are in danger of being destroyed. I was afraid of losing them, more than my own life."
The key to the confusion lies with a controversial piece of legislation, the Subversive Activities Prevention Law, originally drafted for use against terrorist groups like the Japanese Red Army, which carried out kidnappings and hijackings during the 1970s. The law allows the government forcibly to disband a group, seize its assets and ban its activities.
It has never been invoked, partly because of the potential conflict with Japan's post-war constitution, which guarantees freedom of religion and association. But a panel has been convened to investigate the possible application of the law.
According to Mr Asahara's lawyers, it is the threat of dissolution which has finally coerced him into a limited and vague confession. They insist he will plead not guilty at his trial, scheduled for 26 October.
Trials of lesser cult members began a month ago and have proceeded briskly so far, as guilty pleas and expressions of contrition have been rewarded with light prison sentences, often suspended. The case has reflected badly on the police, who suspected Aum of murder as early as 1989, but acted against the cult only after this year's sarin attack.
This week, a manhunt was launched in mountains north of Tokyo for a pair of wanted Aum members. The alarm was raised after the discovery of a makeshift camp, along with 14 bottles of cyanide gas - the same gas used in a failed attack on a Tokyo station in May. Mr Asahara may stand defiantly in the dock, but fugitive disciples may be still at large with quantities of deadly chemicals.