Lee Sang-eun, President Lee Myung-bak’s eldest brother, will be summoned by special investigators on Wednesday in a widening investigation into a property scandal surrounding the first family.

On Wednesday morning, the 79-year-old chairman of automotive seat maker DAS will become the second member of Lee’s family to be questioned by the independent counsel over alleged irregularities in connection with the president’s now-scrapped retirement home project. Lee’s son Si-hyung was grilled on Thursday for over 14 hours as a criminal suspect.

The scandal centers around the joint purchase in May 2011 of a plot of land in Naegok-dong, southern Seoul, by Si-hyung and the presidential security office for the president’s retirement house. The senior Lee lent 600 million won ($547,000) in cash to Si-hyung on Oct. 24, last year, four days after the president’s son came to his office in Gyeongju with a promissory note, DAS officials claimed. He told his nephew such a note was not necessary but received the printed document as Si-hyung insisted, company officials told reporters Monday, just two days before the senior Lee was to step into the special counsel’s office in Seocho-dong.

The president’s eldest brother fanned suspicions about his role in the land deal as he left the country on an alleged business trip on Oct. 16, a day before investigators were to impose a travel ban on him.

Investigators will question him about why he gave the money in cash and asked his wife to deliver the money, instead of transferring it from his bank account to Si-hyung. The team said it will also investigate whether the money came from company funds.

They will trace records of the company’s money transactions if necessary. During the 2007 presidential campaign, the opposition raised suspicions that President Lee was the actual owner of the auto parts maker.

President Lee has three brothers including Sang-eun and Sang-deuk, former vice National Assembly speaker and a six-term lawmaker of the ruling Saenuri Party who is currently on trial over receiving bribes from suspended savings banks in return for business favors.

By Cho Chung-un (christory@heraldcorp.com)