The group has been buying up houses and other real estate across Japan to set up new offices and meeting centers in what authorities describe as an ominous effort to re-establish itself.
Police say members are once again preparing for the Armageddon they have been promised will come this year by their jailed messiah -- Shoko Asahara, who is on trial for murder in the March 21, 1995, subway gassing and other killings.
Aum's re-emergence has unnerved some Japanese, such as those who live near the group's recently purchased house in Kitamimaki, a village about 90 miles northwest of Tokyo.
The spacious two-story house with white walls and black roof tiles has a parking lot for about a dozen cars and is ringed by steel fences installed by the cult.
It also is surrounded by villagers who have been keeping a 24-hour vigil for three months to make sure no one from the cult gets in.
"We will not let Aum come into our village," said Osamu Koyama, the town's mayor.
Aum was stripped of its legal status and tax privileges as a religious organization, but the government concluded it was no longer a threat and stopped short of using an anti-subversion law to ban it. So members can still assemble, spread their ideas and raise money.
Authorities see a disconcerting effort by Aum to expand in a year that is of special significance to Asahara's followers.
According to the guru's teachings, Judgment Day will come on either Sept. 2 or 3 and only cult members will survive.
Possibly in preparation, investigators say, the cult has set up several offices or meeting places around the Tokyo Detention Center, where Asahara is being held while on trial.
"I'm concerned about the situation," said Kenji Kawashima, a cult specialist who teaches at Tokyo's Keisen University. "Many young Japanese can be easily influenced by a cult with teachings that trigger fears about the turn-of-the-century catastrophe."
Aum says its recent activities are not a cause for concern.
"We are only looking for a place to live and practice," the group says on its World Wide Web page.