Samsung Group’s de facto chief Lee Jae-yong on Monday faced questioning from special investigators for the second time as part of a high-profile probe into President Park Geun-hye’s alleged corruption.

“I will faithfully tell the whole truth,” said the Samsung Electronics vice chairman, as he entered the Special Counsel Park Young-soo’s office in southern Seoul on Monday morning.

Lee, 48, is suspected of bribing Park’s longtime confidante Choi Soon-sil to win political support for a controversial merger between two Samsung affiliates in 2015. The Samsung C&T-Cheil Industries deal was made possible chiefly by the support of the state-run National Pension Service, which was the largest shareholder of Samsung C&T. 

The bribery allegations are part of a massive scandal that led the National Assembly to vote overwhelmingly in favor of impeachment Park last December.

“We will decide soon whether to retry arrest of Vice Chairman Lee,” its spokesman Lee Kyu-chul told reporters, as the questioning continued into afternoon.

It is the second time that the billionaire heir has been grilled over the group’s generous provision of support for Choi’s interests and her horseback rider daughter.

The team, after questioning Lee on Jan. 12, sought to arrest the executive last month, but was blocked by a local court, which cited a lack of evidence.

In the second round of questioning, the probe team is said to be focusing on new suspicions about the dubious Samsung-Choi Soon-sil ties. One involves the Fair Trade Commission’s 2015 directive to Samsung SDI to reduce its equity holdings in Samsung Electronics.

The FTC ordered Samsung SDI, a Samsung unit, to dispose of 5 million Samsung Electronics shares to comply with the country’s regulation on cross-shareholding amongst affiliates, three months after the merger in 2015. The counsel team suspects that the presidential office exerted influence to reduce the size of required stock disposal by half from an original 10 million shares.

Earlier this month, the investigators raided the home and office of Kim Hack-hyun, a former vice chairman of the FTC, and questioned him over the suspicion.

According to the probe team, Samsung Group provided or pledged to provide a total of 43 billion won ($37.5 million) to Choi and her daughter, Chung Yoo-ra. Part of the money was delivered in the form of a horse sponsorship for Chung, a former national team dressage competitor. The special counsel is trying to repatriate Chung for questioning. She is currently being held under arrest in Denmark.

Former Health Minister Moon Hyung-pyo was indicted last month on charges of pressuring the National Pension Service to support the Samsung merger, which eventually helped Lee, the only son of Samsung Group chairman Lee Kun-hee, to tighten his grip on the entire group.

Both President Park and Samsung have strongly denied the bribery accusations.

On Monday, two senior executives of Samsung -- Samsung Electronics president Park Sang-jin and senior executive Hwang Sung-soo -- were questioned over whether the sponsorship for Choi’s daughter was under Lee’s instruction. Both had positions at the Korea Equestrian Federation.

This takes the total number of Samsung Group executives called in as suspects to five, including its future strategy office’s Choi Ji-sung and Chang Choong-ki who were summoned earlier in connection with the investigation.

By Bak Se-hwan (sh@heraldcorp.com)