The prosecution has secured a fresh list of politicians who allegedly received illegal funds in a widening probe into a graft scandal.

The list includes officials from the ruling and main opposition parties.

Investigators are considering questioning political heavyweights late next week, starting with South Gyeongsang Gov. Hong Joon-pyo, according to reports. The former ruling party chairman is one of eight whose names appeared in a memo left by former Keangnam chairman Sung Woan-jong before his apparent suicide last week. 

Hong, a former ruling party leader, is accused of accepting 100 million won from Sung through a middleman.

The special investigation team has seized a 30-page secret document from Sung’s aides. It reportedly includes 14 names of political officials, including up to eight from the main opposition party.

Authorities said Friday they were looking into 34 pieces of evidence, including hard drives and cell phones confiscated from Keangnam Enterprise and the late chairman’s aides. The investigation team has sent material to a digital forensic department to restore deleted files, which are believed to contain a list of lawmakers who Sung and his company delivered money to.

Authorities have also reportedly secured surveillance footage of Prime Minister Lee Wan-koo’s campaign office when he was running for a by-election in 2013. Sung claimed he delivered 30 million won to Lee. The prime minister, however, has denied the claim and his ties with Sung.

Authorities have refused to elaborate on plans to summon politicians, citing a lack of evidence.

“For now, we are trying to restore (deleted) files as much as possible in order to go to the next level,“ said an official at the team. “Questioning of (witnesses or suspects) could only start after reviewing documents.”

Amid the prosecution’s widening probe, Saenuri chairman Kim Moo-sung urged the nation to root out rampant political corruption and praised President Park Geun-hye, saying she can effectively lead the anti-graft mission.

Kim and Park met in a closed-door meeting Thursday afternoon before the president left for a 12-day Latin America trip.

The president said she would take every possible means to resolve escalating graft allegations, including launching an independent probe. She also said she would determine the fate of the embattled prime minister after she returns from her trip.

Lee, one of the eight on the graft memo, has been pressured from both parties to step down from his post. But Rep. Moon Jae-in, chairman of the main opposition New Politics Alliance for Democracy, lashed out at the prosecution over reports the authorities could include opposition lawmakers as part of their graft probe.

The prosecution has raided former Keangnam executives who managed finances for the firm between 2002 and 2008, when former liberal President Roh Moo-hyun was in power. He said the prosecution is diluting its ongoing investigation into ruling party members.

“(The prosecution) appears to be attempting to water down the investigation by dragging the opposition party to it. I feel outraged,” said Rep. Moon.

He also urged the prime minister to voluntarily step down from the post, saying it would keep his honor intact and release the political burden from President Park.

Despite mounting calls, Lee told reporters Friday he would focus on state affairs “more diligently” than before during the president’s trip to South America.

Park’s approval rating dropped to 34 percent this week, down 5 percentage points from the previous week, according to local polls by Gallup Korea.

By Cho Chung-un (christory@heraldcorp.com)