Koichi Kitamura, 31, had driven Aum member Kenichi Hirose, 35, to a railway station, where Hirose allegedly spread sarin gas on the Marunouchi line, killing one person and seriously injuring three others, the court ruled.

Kitamura, who has since quit the doomsday cult, was the third of 14 indicted members to be found guilty over the attack on five subway trains in which twelve people were killed and more than 5,300 injured.

Handing down the ruling, Tokyo district court presiding judge Kiyoshi Kimura said the crime caused members of the public immeasurable fear and destroyed their trust in security.