Prosecutors raided two of South Korea's local cryptocurrency exchanges Monday as part of an investigation into the snowballing suspicions surrounding opposition lawmaker Kim Nam-kuk's digital assets, officials said.

A team of investigators from the Seoul Southern District Prosecutors Office seized transaction records and other materials from Upbit and Bithumb, they said.

The move came as Rep. Kim has come under fire following revelations he owned around 800,000 Wemix coins in 2021, worth around 6 billion won ($4.5 million), a significant amount inconsistent with his frugal image. Suspicions have arisen over where the money came from and whether he used insider information.

The first-term lawmaker, who quit the main opposition Democratic Party on Sunday, has also faced allegations he traded cryptocurrency coins while he was attending at least two meetings of the judiciary committee of the National Assembly, which took place in May and November of last year.

Kim operates his digital wallets at Upbit and Bithumb. (Yonhap)