The Tokyo District Court sentenced well-known economist Kazuhide Uekusa to four months in prison Tuesday for groping a high school girl on a train — his third conviction for an indecent act.

Uekusa, 46, was found guilty of violating an ordinance on public indecency. The former Waseda University professor was fined ¥50,000 for a similar offense in 1998 and ¥500,000 in 2005 for looking up the skirt of a high school girl at JR Shinagawa Station with a mirror.

Presiding Judge Sho Kamisaka denounced Uekusa for "lacking the sense of social discipline" and said he was highly likely to be a repeat offender.