While gearing up to question President Park Geun-hye in person over her alleged involvement in corruption, special prosecutors Tuesday added momentum to investigating Park’s close friend Choi Soon-sil and her purported meddling in key state affairs.

They also made last-minute arrangements on the precise date and place to summon the incumbent president, an occasion likely to affect Park’s ongoing impeachment trial at the Constitutional Court.

Investigators, led by Independent Counsel Park Young-soo, on Tuesday summoned South Korea’s Ambassador to Myanmar Yoo Jae-kyung to question him over the allegation that presidential confidante Choi had exerted influence on his appointment.

The 58-year-old diplomat was appointed to his current post in May 2016. As a former senior executive at Samsung Electro-Mechanics, Yoo had no experience in diplomacy.

The investigation team suspects that Choi placed Yoo to the post using her ties to the president so as to gain economic profits through state-funded businesses there.

“I still do not know who recommended me as ambassador,” Yoo told reporters upon arriving at the independent counsel headquarters.

“If somebody did make the recommendation (with an ulterior motive), I can affirm to you that he or she had the wrong person.”

He declined to comment as to whether or not he had actually met her in March, before his appointment.

But contrary to Yoo’s denial, the investigation team claimed the ambassador had admitted to his connection with Choi.

“Though he earlier denied it, (Yoo) admitted that he had met with Choi several times and that he became ambassador upon her recommendation,” said the independent counsel team’s spokesperson Lee Kyu-chul in the afternoon, hours after Yoo went in for questioning.

While chances are low the ambassador will face indictment, his remark is likely to add another bribery charge to Choi.

According to the investigation team, Choi had received kickbacks in exchange for having a Myanmarese company included in the K-Town Project, a 76 billion won ($65.3 million) deal to build a convention center in the Southeast Asian state. The project, however, later fell apart amid disputes on its legitimacy and profitability.

“We expect to request an arrest warrant for Choi (regarding her bribery charges related to the Myanmar business),” Lee said.

On the previous day, the embattled presidential confidante refused to respond to a summons on her bribery allegations connected to Samsung Group and other conglomerates.

Meanwhile, speculation mounted on the scenario that investigators will question the president in person between Feb. 8 and Feb. 10, though the exact date, time and place are yet to be decided.

“We plan to carry out a search and seizure of Cheong Wa Dae and a face-to-face questioning of the president in February,” counsel spokesperson Lee Kyu-chul said Tuesday.

The place could be either the Blue House or another location, as the independent counsel office does not have the necessary security conditions, according to officials.

Among the charges raised against the president is the allegation she exerted power to help conglomerates, including Samsung Group, in exchange for benefits offered to confidante Choi and her daughter Chung Yoo-ra.

But despite the president’s promise to respond to the independent counsel’s summons, it is uncertain whether she will attend, especially considering the increasing complaints she and her legal representatives have levied against the ongoing investigation.

“I am planning to cooperate with the investigation,” Park said in a rare interview with the chief editor of the Korea Economic Daily, which aired via YouTube on Jan. 25.

The president had made a similar promise last year to fully cooperate with the prosecutors’ investigation, but altered her stance as soon as investigators named her an accomplice in Choi’s alleged wrongdoings.

Also, dispute arose Tuesday following reports the president had ordered her staff to uncover investigation secrets, a story Blue House spokesperson Jung Youn-kuk immediately denied.

By Bae Hyun-jung (tellme@heraldcorp.com)