Prosecutors said Wednesday they have ordered a former vice chairman of Samsung Group to undergo questioning over alleged bribery involving former President Lee Myung-bak.

Lee Hak-soo, who headed the now-disbanded Samsung control tower between the late 1990s and 2000s, was summoned to appear at the Seoul Central District Prosecutors' Office on Thursday, according to the prosecution. The prosecution raided his home last week as part of the probe.

Lee, 72, is expected to be grilled over his involvement in Samsung's alleged payment of fees to a US law firm for DAS, a local auto parts maker run by the ex-president's family.

DAS raised a suit against an investment advisory firm there, seeking to recoup its 14 billion-won ($13 million) investment in the company.

Akin Gump, the law firm that took the DAS' case, already had Samsung as one of its clients.

Prosecutors suspect the payment was a bribe from Samsung in return for a favor from the Lee government, since the tech behemoth had no connection with DAS.

Given the timeline of the events, the prosecution suspects that it may have been related to the special pardon of Samsung Chairman Lee Kun-hee granted by the former president in 2009. Lee was convicted of embezzlement and other charges in a slush fund scandal.

DAS is owned by a brother of the former president, but Lee has long been suspected of being its real owner. The company is also under investigation over suspicion that it created a 12 billion-won slush fund for the former president, whose five-year term ended in early 2013. Lee has denied the accusations.(Yonhap)