Arrested former Justice Minister Katsuyuki Kawai and his Diet member wife, Anri, may have distributed around ¥30 million ($280,000) in cash to some 100 people in their alleged plot to buy votes for the Upper House election last summer, a source familiar with the matter said.

Lists that were likely used to record who got how much have been confiscated by Hiroshima prosecutors from the couple's home, the source said Friday.

The 57-year-old former minister, known for his close ties to Prime Minister Shinzo Abe, was arrested along with his wife Thursday on suspicion of giving out ¥25.7 million in cash to 94 local politicians and supporters as rewards for their efforts to secure votes for her in the House of Councilors election last July.