Prosecutors investigating a cash bribery scandal connected to the main opposition Democratic Party's 2021 leadership election once again summoned a suspect accused of procuring the illicit funds.

According to legal sources, Kang Rae-gu, an audit committee member for the state water agency K-water, was called in for questioning for the second time on Wednesday at the Seoul Central District Prosecutors’ Office after the first inquiry on Sunday.

Kang was reportedly grilled on the extent of Song Young-gil's involvement ahead of his victory in the election for chair, from knowing about the cash envelopes to ordering their distribution.

Prosecutors suspect Democratic Party Rep. Youn Kwan-suk and Kang led the illegal disbursement of funds within the party ahead of the convention to help Song win.

Kang is believed to have procured 80 million won out of the 94 million won total from acquaintances including a businessman based in Daejeon.

Kang is reportedly denying most of the allegations. Given the gravity of the case, the prosecution may request a warrant to arrest him in the coming days.