Tokyo prosecutors on Thursday arrested former Liberal Democratic Party lawmaker Mito Kakizawa for allegedly giving bribes to assembly members in Tokyo’s Koto Ward to garner support for a candidate in the Koto mayoral election.

Four secretaries of Kakizawa, 52, were also arrested for their involvement in the bribery case. Namely, Masaki Ito, 52; Naruto Yuruki, 64; Shu Goto, 38; and Naoki Morikawa, 34.

Investigators suspect Kakizawa handed a total of ¥1.8 million in cash to LDP assembly members before the election in hopes of getting Yayoi Kimura elected. He is also suspected of offering ¥800,000 to a former assembly member involved in the election campaign for Kimura as an “advisory fee."

Kakizawa has reportedly denied the charges, saying he did not intend to bribe the assembly members with the cash. But some of those who received the money have told investigators that they thought it was bribery.

Kimura, 58, the mayoral candidate backed by Kakizawa, won the election in April, but she resigned in November amid allegations that she and her campaign staff posted a paid advertisement on YouTube for about ¥380,000, calling for people to vote for her, in violation of the election law.

Kakizawa is suspected of proposing the YouTube ad to Kimura and her staff in the first place. As investigators looked into the case, allegations that Kakizawa was also involved in bribery began to surface. Kakizawa was also arrested Thursday over the alleged YouTube ad post.

The Lower House member resigned as deputy justice minister in October over the YouTube ad. Kakizawa also left the LDP earlier this month after prosecutors raided his office in the Nagatacho district of Tokyo, but he remains a lawmaker.

Those who violate the public offices election law with regard to vote-buying face imprisonment of up to three years or a fine of up to ¥500,000. Those who use paid advertisements online for specific candidates face imprisonment of up to two years or a fine of up to ¥500,000.

Information from Kyodo and Jiji added