Lee Wan-koo only became prime minister of South Korea in February after a tough parliamentary fight for confirmation, during which a recording of him surfaced in which he boasted of his ability to suppress bad press coverage.
Mr Sung left a suicide note - a suicide accusation, would be more accurate - in which he named those whom he claimed had taken his tainted money.
The South Korean prime minister's name was on that list.
The resignation came shortly after the prime minister had declared an "all-out war" on corruption, saying the government would mobilise all its resources to root it out.
Mr Lee initially showed no sign of vacating his seat, denying the allegations - and then after a weekend of feverish speculation - he offered his resignation, still denying the allegations.