A former national lawmaker from Japan's top opposition party and two of his aides have been accused of possessing amphetamines following a six-month investigation.
Kenji Kobayashi, his private secretary Koshi Ando, and former secretary Masaharu Saeki were arrested on Sunday.
Kobayashi was immediately expelled from the Democratic Party of Japan, according to the party's Web site.
Kobayashi lost his seat in the lower house of Parliament in Sept. 11 elections, when the DPJ suffered a major defeat at the hands of the ruling Liberal Democratic Party. He was first elected to Parliament in 2000 and re-elected in 2003.
The three suspects, arrested in the Nagoya area, 270 kilometers west of Tokyo, have admitted that they were using the stimulants for personal use, the national Asahi newspaper reported, citing police.
But an official with the Showa city police, near Nagoya, who also spoke on condition of anonymity, said authorities were still investigating whether Kobayashi used the drugs while he was a lawmaker.
The investigation into the three suspects began when police received an anonymous tip in March, the official said.
According to the AP, the arrest comes as the DPJ is in disarray following the electoral defeat. The party named a new leader on Saturday, Seiji Maehara. Kyodo News agency reported that Maehara apologized for Kobayashi's arrest and said such actions deepen public distrust of politicians.