Members of the his Aum Shinrikyo cult punctured plastic bags to release sarin nerve gas inside train cars, killing 13 people and sickening more than 6,000.
The German government has described the death penalty as "inhumane and cruel" after Japan hanged seven members of the doomsday cult that poisoned commuters in a deadly subway attack in 1995.
Asahara had been on death row for masterminding a 1995 sarin gas attack on the Tokyo subways and other crimes.
Six other people are still sentenced to die in connection to the 1995 attack and other Aum Shinrikyo crimes.
In all, 13 cult members were sentenced to death during more than 20 years of trials, which came to an end in January 2018.
"The fear, pain and sorrow of the victims, survivors and their families - because of the heinous cult crimes - must have been so severe, and that is beyond my imagination", Justice Minister Yoko Kamikawa told a news conference.
The agency said it searched a total of 16 facilities of three groups across Japan on Friday, including those of the cult's successor Aleph and the Hikarinowa, or the Circle of Rainbow splinter group launched by former AUM spokesman Fumihiro Joyu.
Asahara, the 63-year-old self-styled religious leader was hanged shortly after dawn at the Tokyo Detention House, more than 23 years after he was arrested.
Amnesty International lamented the executions, saying that these failed to deliver justice and is "the ultimate denial of human rights".
Fresh feel as Europe and South America resume World Cup combat
They will need to rectify those mistakes against a strong Brazilian team which has improved with each passing game. On Tuesday, the end of the round of 16 stage, England defeat Colombia on penalties to reach the quarter-finals.
Seven members of the doomsday cult Aum Shinrikyo were executed in Tokyo on Friday, July 6.
The images of bodies, many in business suits, sprawled across subway platforms stunned Japan, and triggered public safety steps such as the removal of non-transparent rubbish bins that remain in force to this day.
This photo from 1995 shows subway passengers affected by sarin nerve gas being carried into a hospital.
The subway attack was the most notorious of the cult's crimes, which was blamed for 27 deaths in all. At its peak, Asahara had tens of thousands of followers worldwide. The initial death sentence in 2004 became final after his defense team could not file an appeal citing his mental state.
What is the Aum Shinrikyo cult?
The group's founder, Shoko Asahara, also known as Chizuo Matsumoto, declared himself to be both Christ and the first "enlightened one" since Buddha.
He pleaded not guilty and never testified, but muttered and made incoherent remarks in court during the eight years of his trial.
Many of Asahara's followers were highly educated scientists and engineers, who helped bring in huge amounts of money to the cult's coffers.
In 2016, police in Russian Federation conducted a number of raids on suspected cult members in Moscow and St Petersburg.