The prosecution said Sunday that it had secured evidence to prove that South Gyeongsang Province Gov. Hong Joon-pyo met a former aide of deceased businessman Sung Woan-jong that counters the politician’s denial that the meeting took place.

Sung’s aide, surnamed Yoon, has claimed to have delivered illicit money from the businessman to Hong in 2011 when he was running for chairmanship of the Grand National Party, the precursor to the ruling Saenuri Party.

An official at the special investigative team told reporters that Hong was confirmed to have met with Hong at the time of the supposed transaction.

Hong is among eight politicians whom Sung claimed to have given illegal political funds to before his death last month. On Friday, he became the first of the eight to be questioned by the prosecution, after Yoon said he delivered 100 million won ($92,000) to Hong’s secretarial staff in June 2011.

While Hong repeatedly denied the charges and insisted that he never met Yoon prior to November 2011, investigators said they acquired evidence verifying Yoon’s testimony to be accurate.

“We’ve acquired all the solid proof (on whereabouts of Hong), so we don’t think there is any doubt about it,” the prosecution’s special investigative team on the case said.

Contrary to Hong’s claims, Yoon told investigators that he met Hong and his staff at a building in the National Assembly in June. Prosecutors reportedly procured a photo of Hong’s party in the building at the said time.

The investigators were to summon Hong’s former aide -- who worked as his secretary during a 2011 primary election of his party -- later in the day to verify the governor’s testimonies.

The prosecution suspects Hong’s staff received the money while he was running for the leadership of the Grand National Party. They are strongly considering filing charges against him for violation of the political fund act.

As part of an ongoing probe into a burgeoning graft scandal, the investigation is now expected to zero-in on former Prime Minister Lee Wan-koo, another of the eight who supposedly received money from Sung.

According to sources, the prosecution is likely to summon Lee this week to question him over allegations that he received illicit political funds in 2013.

Besides Hong and Lee, the so-called “Sung Woan-jong List” also includes three of President Park Geun-hye’s former and current chiefs of staffs, two mayors and a lawmaker of the ruling Saenuri Party.

It sparked a graft scandal that saw the resignation of the prime minister -- who held office for just two months -- and the plummeting approval ratings for Park, coupled with attacks from the opposition on the administration’s integrity.

On Saturday, the special investigative team grilled Sung’s aides including his driver and his secretary, who accompanied the chief of former Keangnam Enterprises when he is believed to have visited Lee’s campaign office in 2013. They also summoned a volunteer at the office who claimed to have witnessed Sung at the site.

Sung claimed he handed Lee the money during the visit, according to an interview he gave a local newspaper just before his death.

Lee has denied the allegations that he had a private one-on-one meeting with Sung, but his former driver told local media that he witnessed the two having such a meeting. The investigators questioned the driver -- identified by his surname Yun -- on Wednesday.

The focal point of the investigation on Lee is when and how the money was handed over to the former premier -- if such a transaction had taken place at all. Initial investigation implied that the supposed transaction occurred on April 4, 2013, when the cited volunteer testified to having seen Sung at the campaign office.

But further investigations dug up another potential date of April 7, when Sung visited a region in South Chungcheong Province near where Lee was conducting his election campaign.

The prosecution is also probing the suspicion that Lee’s former aide -- surnamed Kim -- had called Yun and the volunteer to persuade them not to testify.

By Yoon Min-sik (minsikyoon@heraldcorp.com)