A brother of South Korean President Lee Myung-bak appeared before prosecutors on Tuesday to answer questions about a savings bank graft scandal.
Lee's three predecessors all saw their sons or brother prosecuted for taking bribes in return for the promise of influence.
The president's brother, Lee Sang-deuk, was summonsed to appear at the Supreme Prosecutors' Office to answer questions about the collapse of a savings bank which forced more than a dozen small institutions to shutdown and thousands to lose their savings. Lee has no direct links to the collapsed bank.
Some of President Lee's closest aides and political allies have been convicted or put on trial in the savings bank scandal, where operators of failing financial firms paid off the officials to cover up mismanagement.
Lee was driven through a crowd of angry depositors demanding justice, after losing their savings, exceeding a 50 million won ($43,600) state deposit insurance.
"I am fed up with current politics. Existing politicians, whether left or right, are all the same. Corrupt Republic of Korea!" said Choi Tae-hoon, a 51 year old fisherman protesting in front of the prosecutors' office.
Arriving at the prosecutors' office, Lee declined to answer questions from reporters.
Lee was a successful businessman before serving six terms in parliament and has been a powerful presence in politics.
The banking scandal has had little impact on the financial integrity of Asia's fourth largest economy, but has dealt a heavy blow to the political credibility of Lee's government.
The outcome of the probe, which is likely to involve other high-profile lawmakers, is unlikely to affect the upcoming presidential election in December.
A long-time rival of the president in his ruling conservative party is the frontrunner in a race where jobs, economic equity and welfare are likely to dominate the campaign.
Park Geun-hye, who is daughter of assassinated dictator Park Chung-hee, has kept her distance from Lee and has remained silent on the sidelines since her primary defeat five years ago while trying to project an image of a clean leader.
Despite years of work to clean up the country's image as a place where bribes and backroom dealings were prerequisites to getting business done, South Korea continues to rank poorly in corruption surveys and graft remains a regular feature of bitter politicking ahead of key elections.