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.

“The court cannot anticipate that the accused will be rehabilitated” on his own recognizance, Kamisaka said in explaining why he did not hand down a suspended prison term.

According to the court, the economist put his hands under the high school student’s skirt while on a Keihin Kyuko Line train near Shinagawa Station at around 10:10 p.m. Sept. 13, 2006. He attempted to hang himself with his necktie after being seized by other passengers.

Although Uekusa denied committing sexual assault and claimed he was drunk at the time and thus cannot recollect what transpired, witnesses confirmed his culpability, the court said.

Forensic evidence also verified a match between fabric traces found on Uekusa’s suit with that of the victim’s skirt. In demanding a six-month prison term, prosecutors argued Uekusa damaged the victim’s dignity and that he was highly probable to repeat the offense.

Uekusa said he intends to appeal the ruling, issuing a statement saying “the truth will always prevail.”

A University of Tokyo graduate and former visiting fellow at Stanford University in the U.S., Uekusa frequently appeared on TV as a commentator on economic issues. He fell into disrepute after the mirror incident at Shinagawa Station made headlines.

After his most recent arrest, Uekusa lost his job as a visiting professor at Nagoya University of Commerce and Business.