SEOUL, Dec. 6 (Yonhap) -- Prosecutors said Tuesday they plan to summon this week the chairman of SK Group, the third-largest industrial conglomerate in South Korea, on suspicion that he embezzled nearly 100 billion won ($88.4 million) of group funds in collusion with his younger brother.

The summons of Chairman Chey Tae-won will take place this week although prosecutors have yet to decide exactly when to call him in for questioning, the prosecution said.

The plan was revealed following the prosecution's 16-hour interrogation last week of Chey Jae-won, the chairman's younger brother and group vice chairman.

The vice chairman will appear before prosecutors for another session of questioning on Wednesday, less than a week after the first interrogation, the prosecution said.

The brothers, sons of group founder Chey Jong-hyon, are facing allegations that they misappropriated the funds, which were part of a total of 280 billion won 18 SK affiliates set aside for investment purposes.

The embezzled funds were reportedly used to make up for as much as 300 billion won in losses incurred as a result of 51-year-old Chairman Chey's unsuccessful stock futures investment.

The younger brother is suspected of having primarily led the embezzlement scheme.

The vice chairman reportedly refuted the embezzlement accusations during the interrogation last week, but prosecutors are believed to have secured evidence suggesting the two brothers' illegal use of the affiliates' funds.

Chairman Chey was summoned by prosecutors in 2003 while he was facing accusations of accounting fraud and illegal acquisition of his firm's own stocks in a bid to block hostile foreign takeover attempts.

He was convicted of the charges and sentenced in 2005 to a three-year prison term, suspended for five years.

SK Group controls dozens of affiliates in various industrial segments, including top oil refiner SK Innovation and No. 1 wireless telephone service provider SK Telecom.