TOKYO - Former Japanese justice minister Katsuyuki Kawai and his lawmaker wife Anri Kawai have been arrested by prosecutors over an alleged violation of the election law, local media reported Thursday.

Katsuyuki Kawai, 57, a member of the lower house of parliament, and his wife are suspected of buying votes in the upper house election last July in which Anri Kawai, 46, won her seat in the poll, in potential violation of the Public Offices Election Law.

The previous day, the pair embroiled in the scandal asked for their membership to the ruling Liberal Democratic Party (LDP) to be withdrawn, and their letters of resignation were accepted by the party.

Despite the weighty allegations against them, the pair have said they do not intend to give up their seats in parliament.

Katsuyuki Kawai, according to investigators, may have given out over 24 million yen ($225,000) in cash to numerous local legislators.

Katsuyuki Kawai, who served as Prime Minister Shinzo Abe's special adviser for foreign affairs before assuming his first ministerial post in charge of justice in a cabinet reshuffle in September last year, is known to have close associations with both the prime minister and Chief Cabinet Secretary Yoshihide Suga.

He is believed to have offered between 50,000 and more than 100,000 yen ($930) in cash to each of the couple's supporters in their constituencies, prefectural and city assembly members, as well as local government chiefs.

Anri Kawai is also suspected of handing out around 1.5 million yen ($14,000) in cash to around 100 local voters to garner their support.

Of the 100 questioned on the matter, the majority admitted to prosecutors to having received the illicit handout from Anri Kawai.

Prosecutors alleged that the pair's actions violated the Public Offices Election Law and had been planning to question the couple on Thursday, once the current Diet session, which ran through Wednesday, ends.

In Japan, while the Diet is still in session, lawmakers have special immunity from being arrested.