Prosecutors are looking into allegations of bribery and false testimony against Lee, the heir and de facto leader of the Samsung Group, officials said on Wednesday.

"We have decided to question Lee tomorrow morning... as a suspect," spokesman Lee Kyu-chul told reporters in Seoul.

Samsung did not immediately comment on the announcement.

According to legislators and the South Korean media, Samsung had made a deal with the company of Choi Soon-sil, the key figure in the political scandal that threatens to unseat South Korea's President Park Geun-hye. The tech giant allegedly paid Choi's firm $18 million (17.06 million euros) and donated another $17 million to two nonprofit foundations linked with her.

Samsung money to buy horses

Prosecutors are now investigating whether this deal helped Samsung secure a controversial merger in 2015. The decision involved the National Pension Service, which  backed the move despite its advisors. The ex-minister, who was overseeing the fund at the time, has been arrested.

Authorities claim to have found details on dealings with Samsung while examining a tablet PC of Choi Soon-sil. Part of the Samsung funds was allegedly used to buy expensive horses and pay for equestrian training for Choi's daughter,who is a member of the South Korean national team.

Two other Samsung executives were questioned as witnesses earlier this week.

President waiting for court decision

The Samsung Vice Chairman has taken the lead after his father Kun-hee suffered a heart attack in May 2014. The 48-year-old heir to the Samsung empire appeared on a public hearing over the scandal in December, when he denied that that his company paid for Choi Soon-sil's influence.

At the same time, he added it was "inappropriate" but "inevitable" to send money to Choi, without providing details. He also said he was not aware of the decision to fund her daughter.

The prosecutors are now considering whether Lee gave false testimony before the parliament. The lawmakers have already voted to impeach President Park, but the decision needs to be confirmed by the Constitutional Court.

dj/mg (Reuters, AFP, AP)