Angry depositors threw eggs at the elder brother of South Korean President Lee Myung-Bak as he arrived for questioning on Tuesday about a major savings bank scandal.
Lee Sang-Deuk, a six-term former lawmaker of the ruling conservative party, also had his necktie grabbed and was yelled at by dozens of protesters as he entered a Seoul prosecutor's office.
He is being questioned but has not been charged in relation to the influence-peddling affair, in which operators of troubled savings banks allegedly bribed powerful figures for protection.
Regulators in May suspended operations of several savings banks, leaving many customers unable to withdraw money.
"Give back my money! Give back my money!" and "Arrest Lee Sang-Deuk!" angry customers shouted as the 76-year-old arrived.
The scandal is the latest in a series of corruption cases involving close aides of the president, whose five-year term ends in February 2013.