The head of a support group for Kenji Koso, a former postal official who won his first Diet seat in the July 29 House of Councilors election, was arrested Tuesday on suspicion of campaign infractions, the latest in a string of alleged violations linked to the lawmaker.
Police said Tadashi Kobayashi, 72, was arrested on suspicion of breaking the Public Offices Election Law by requesting the support of a senior postal official in Koso's campaign. Koso went on to collect some 480,000 votes as a Liberal Democratic Party candidate.
Kobayashi, a former postmaster at the Osaka Chuo post office, became the 16th person arrested in the case. He was, however, the first senior official of Koso's support group to be arrested.
Investigators also plan to ascertain whether Koso was involved in the alleged vote-canvassing.