Imagine what it is like to live next door to an organisation that a few years ago launched a chemical attack on your own city.
The residents of a quiet street in downtown Tokyo where what is left of the former Aum Shinrikyo cult lives, know just how frightening it is.
As you approach the cult headquarters you see long white banners reading "Get out of here Aum".
Before you can go inside, a policeman checks your bags.
The neighbourhood watch lady wants to know what you are up to. It is all rather sinister.
And yet when you meet the cult members they are quietly spoken, friendly and rather disarming.
These days the cult calls itself Aleph.
It has renounced the violent teachings of its former leader Shoko Asahara.
Now about 100 members occupy a large apartment block, living together, worshipping together and trying to keep a low profile.
The cult agreed to talk to me though, because its guru Asahara could be hanged soon.
There is some concern in Japan that that might make him a martyr.
No-one knows how his former supporters might react and Aleph wanted to make clear to the rest of the world that they do not pose a threat.
Araki Hiroshi, Aleph's spokesman - who is stick thin and has the air of a monk about him - gave long and considered answers to all of my questions.
Like his companion, Matsuo Nobuyuki, he was a member of Aum before the attacks.
But both men claim they had no idea what was going to happen.
"I joined in 1990 thinking it was a religious organisation," Matsuo told me. "Five years later I found out I'd joined a terrorist organisation."
The security services have raided their premises more than 100 times in the last six years.
But the men insisted they and other members of the cult do not pose any threat to anyone.
"Why those crimes were committed under the aegis of religious teaching and what our leader was thinking we have no idea," Araki told me.
They were at pains to stress that the new organisation was really different to that led by Asahara.
I do not know if I believe them.
Although there were no portraits of Asahara in the room where the interview took place there was a large stone that they worship, a stone they told me that had been "energised" by the guru.
They say they believe in the "Shoko Asahara who lives in the religious world and not the Shoko Asahara who committed those crimes".
That is a distinction the rest of Japan finds quite difficult to understand and, as a result, quite unsettling.
Just how nervous the Japanese are about the cult and anything to do with it was confirmed for me a couple of nights later when I met two of Shoko Asahara's daughters at the office of his lawyer.
Neither of the two women was prepared to reveal her name.
One was wearing a wig to partially hide her identity.
The other looks strikingly like her father. She says that wherever she goes, as soon as people realise who she is, she is hounded.
"The public want us to be unhappy, to suffer," she told me.
"When Aum first went bankrupt we left the headquarters. But the police, the public security officers and the media followed us everywhere. We were under surveillance all the time.
"Then there were demonstrations. I had to leave school. Every time people found out who we were, the protesters began to kick us out."
The two women are now trying to save their father from the gallows.
They believe he is mentally ill.
After years of solitary confinement he does not recognise them, they say.
"He's incontinent. He mumbles incoherently and has no idea what's going on."
They want the legal process halted.
Like Araki and Matsuo from Aleph, their strongest argument is that Shoko Asahara should be spared and his mental illness treated in an effort to persuade him to give his side of the story.
They too say they want to hear why he ordered the attacks.
But the courts disagree.
They have decided that the cult leader is able to understand what is going on but chooses not to.
His appeals process is coming to an end and he could be executed at any time.
But that will not be the end of the story.
At Aleph headquarters they told me they found their faith through meeting him. That is where they started. He is the foundation of their religion.
Shoko Asahara has no official position in Aleph itself, they say.
But every member holds his image in their minds.
And that is why their neighbours continue to worry.