The special investigation team has imposed travel bans on conglomerate chiefs as it prepares to dissect the political scandal involving President Park Geun-hye and her confidante Choi Soon-sil, according to news reports on Sunday.

Samsung Electronics’ Vice Chairman Lee Jae-yong, SK Group’s Chairman Chey Tae-won and Lotte Group’s head Shin Dong-bin have been banned from travelling abroad.

The ban came as the independent counsel team is set to begin a 70-day investigation into the scandal from Monday. The probe will focus on whether the combined donation of 77.4 billion won ($65 million) from the companies to the Mir and K-Sports foundations were bribes for the President and Choi. 

Samsung Group donated the largest amount of money -- 20.4 billion won -- through its several affiliates after Lee privately met with President Park in July of last year. Samsung Electronics separately sent money four times to Widec Sports, a German company Choi used to buy horses for her daughter, Chung Yoo-ra. A total of 10 billion won was sent from September of last year to June of this year.

The prosecutors have suspected that Samsung had donated the money to the government in return for favors, including the National Pension Service’s backing of the merger between Samsung C&T Corporation and Cheil Industries last year.

Lee denied the allegation during a parliamentary hearing held on Dec. 6.

“We donated the money inappropriately,” Lee had said, but added, “We did not want anything in return for the donation.”

The special prosecutors will also be investigating bribery suspicions involving Lotte and SK, which were asked to additionally donate 7 billion won and 8 billion won, respectively. Lotte gave 7 billion won in the end of May, but received the money back right before the prosecutors’ raid for a separate investigation, which was carried out on June 10. SK Group reportedly rejected the additional donation.

The independent counsel aims to complete the investigation by the end of February before the Constitutional Court decides on the impeachment of the President Park Geun-hye, which is expected to be early March. 

By Shin Ji-hye (shinjh@heraldcorp.com)