The new figurehead of the Aum Supreme Truth doomsday cult left Japan for Russia on Thursday in an apparent bid to shore up the loyalty of followers there.
The trip came amid expectations that prosecutors would demand death for Aum founder Shoko Asahara, 48, at his seven-year-old trial in two weeks' time.
Fumihiro Joyu, the 40-year-old former telegenic spokesman for the cult responsible for the 1995 deadly gas attacks on Tokyo subways, left on a Aeroflot plane from Narita airport, a public safety source in Tokyo said.
The Russia visit, expected to last for about a week, is his first overseas trip since Joyu was released from Japanese jail in December 1999 after serving a three-year jail sentence for perjury.
"We presume he is trying to tighten the reins on followers there (to prevent them leaving the cult) as the prosecution is expected to announce their demand for Asahara's penalty soon," said the source who declined to be named.
Since prosecutors are likely to demand capital punishment, Joyu "needs to prevent the followers from being shaken" and leaving the sect, the source said.
Japan's security authorities believe there still are about 300 Aum followers in Russia.
As one of the longest-serving disciples of Asahara, Joyu was in Russia running Aum's Moscow branch when the sect spread Sarin gas in crowded Tokyo subways in March 1995, killing 12 people and injuring thousands.
The sect has since officially deposed Asahara as its leader and vowed to fundamentally reform under the new name Aleph.
"I want to explain to old followers (the new policy of Aleph) and lead things in a good direction," Jiji Press quoted Joyu as saying at the airport.
Joyu used to say he worshipped Asahara as a "messiah." After his release from jail, however, he said he had lost faith in his guru because prophecies of Armageddon never came true.
Asahara has denied masterminding the Tokyo subway attack and has blamed his disciples, despite testimony from most followers that the offences were commited under his direction.
The cult's guru has made virtually no statement at his trial, which opened in April 1996, since January 1998 when he denied masterminding the Tokyo subway attack, apart from murmuring incoherently, and has often appeared to doze during proceedings.
He was given a last chance to speak on Thursday but has so far refused even to answer his own lawyers' questions.
On April 24, prosecutors are expected to sum up their case against Asahara who is charged with murder and various other crimes.
Nine of his disciples have so far been sentenced to death for their part in the Tokyo gas attack, another gassing in 1994 that killed seven people in the central Japan city of Matsumoto and other murders, including the strangling of the entire family of an anti-cult lawyer.