The group's website shows smiling followers in flowing robes and police say it clearly has enough money coming in - whether in the form of donations or businesses that conceal the true destination of the earnings - to fund further expansion of its facilities and properties.
But, they say, you only have to scratch the surface to see that Aum Shinrikyo still lurks inside.
"The attitude of the cult's followers is exactly the same as it was 10 years ago, when Shoko Asahara was in control," Minoru Ishida, an investigator with the Public Security Agency, said.
The agency is tasked with keeping an eye on the cult, which changed its name in 2000, after the arrest of Asahara and his top assistants.
"We have to be very careful with them and we are trying to keep a closer watch on their training methods, but it is very difficult," he said.
That observation is not only intended to protect Japanese society as a whole, but also the group's own followers from some of its more bizarre rituals.
The cult's guru, Shoko Asahara,
is awaiting the death penalty
In early January, Wakashio Togashi was found dead in a bath tub after three hours in scalding hot water. Known as thermotherapy, followers believe they are purified by the agonising rite, and Togashi's death was at least the second attributed to its effects.
Togashi was apparently one of the hardliners that still slavishly follow Asahara's teachings, and served an eight-year prison term for abetting seven murders by adapting a van to release sarin in a residential area of the town of Matsumoto in June 1994.
He also helped build the sarin-manufacturing plant at the cult's compound in the mountains of Yamanashi prefecture.
In September, another follower was beaten with a bamboo sword at a Tokyo apartment as part of a ritual to remove her "bad karma". The woman died and four people - including a girl of 16 - were arrested.
But still people continue to join an organisation that has grown to 1650 followers in Japan and another 300 in Russia. At its peak, Asahara ruled more than 10,000 people in Japan and a further 30,000 in Russia but that declined to a handful after the cult used sarin against commuters, killing 12 people.
Scared to leave
"The short explanation for why they stay in the cult is because they have been told they will go to hell if they leave," said Shoko Egawa, a journalist and author who has written about Aum for 15 years and who nearly died after a cult member released phosgene gas in her apartment when she was asleep.
The group was responsible for
sarin attacks at several locations
"According to the doctrine of Aum, those who sin against 'the truth' - which means Aum - have to stay in hell forever, which is very frightening for them," she said.
"They also feel oppressed by Japanese society - these are the same people who were bullied at school or became hikikomori (hermits) - and they are not confident about being able to live in this society.
"As long as they remain in the cult, they believe they are saints and they look down on the rest of us as being ignorant," she said. "The cult controls their minds and makes them feel superior to ordinary people, and that makes it easier for them to stay with their own kind."
From its inception, the cult targeted intelligent but lonely and vulnerable youths from Japanese universities. These men and women were later to set up Asahara's facilities to produce sarin, guns and drugs, including LSD.
To give itself an air of legitimacy - and earn badly needed cash - the cult has set up more than a dozen companies, according to the Japanese authorities.
The cult says these firms, mostly dealing in computer software, will earn money to compensate the victims of the previous regime's errors.
Other followers have joined legitimate companies and are donating their salaries to the cult.
"Aum got rich in the 1980s and 90s because there was so much money out there then, and you can't build a factory to make poison gas on a shoestring"
American journalist and author
To date, 13 Aum followers have been sentenced to death, including Asahara, although none of the executions has yet been carried out.
A spokesman for Aleph refused to comment on the death of Togashi or the cult's present recruiting activities.
But not everyone believes the cult can still be a danger to the public.
"Aum is being mopped up in stages and poses no threat to anyone but its own members, as this latest incident shows," Mark Schreiber, an American journalist and author who has followed the case for the last decade, said.
"This death came as a bit of a surprise, although it was not uncommon back in the cult's heyday, when people disappeared regularly."
He added: "There are some who say that as many as two dozen people just vanished and their families could not get past the cult to trace them."
There were also reports that the cult operated a clinic in Tokyo where older members went for treatment, Schreiber said, and after they had signed away their possessions to the cult in their wills, they were euthanised.
The group's website shows many
"Aum was a product of the bubble economy," the journalist said. "They got rich in the 1980s and 90s because there was so much money out there then, and you can't build a factory to make poison gas on a shoestring.
"That money just isn't there any more, and the only reason the police are harassing the cult is to stop it reorganising and to try to trace revenue that has been put at $1.5 billion at its peak to compensate the families of the victims."
But others disagree, and say Aleph is simply playing a waiting game.
"The cult is very tactical," Ishida, the Public Security Agency investigator, said.
"They set up yoga schools and hide the fact that they are Aum or Aleph and, at first, people don't realise. Then, gradually, they find out the people who are most likely to join them and start explaining their philosophy to them.
"It's amazing, but some people still join them even when they find out that it's Aleph," Ishida added.
"This cult chooses people carefully and makes them feel special and spiritual, and even though it is very hard for us to understand why, some people decide to stay."