Hamstrung by allegations of evidence fabrication, the prosecutors’ office is facing a major crisis.

The developments that threaten to undermine not only the prosecutors’ office but also cast doubt on the integrity of South Korea’s entire legal system began to play out last year when a former Seoul city official was tried on charges of espionage.

Although the defendant, Yoo Woo-seong, a North Korean of Chinese descent who came to the South in 2004, was initially acquitted, the prosecution appealed with new Chinese documents allegedly proving that Yoo had traveled to North Korea as late as 2006.

The Chinese Embassy in Seoul, however, has since stated that the documents were forgeries, sending a shock wave that is now amplifying by the day. The prosecution has yet to produce convincing explanations about the true sources of the documents. It has embarked on an internal investigation into possible flaws in the evidence gathered for the Yoo case, but criticism is mounting over its secretive investigation methods, which often raise questions about their motives.

Prompted by the allegations, the main opposition Democratic Party, which is calling for a major reform of the investigative organization, is ratcheting up the pressure on the prosecutors’ office.

The DP is operating a special committee to get to the bottom of the spy evidence scandal, and its members are said to have found no proof that the documents in question were obtained through official channels at the Shenyang mission on Tuesday.

The near absence of proof backing up the prosecution’s claims is also undermining the already precarious position of the National Intelligence Service, which has been under fire since the 2012 presidential election for allegedly attempting to sway public opinion against the opposition candidate.

Although the NIS has compiled a report supposedly proving the documents’ authenticity, the spy agency’s move only appears to be adding fuel to the fire.

DP spokesperson Rep. Han Jeoung-ae said Wednesday that the NIS had maintained the authenticity of the documents but suddenly changed its position Tuesday, saying the documents had been obtained through unofficial channels by one of its agents.

“In other words, it has verified they are not official documents,” Han said.

She added that the prosecution’s investigation into the fabrication scandal might be conducted in a way that protects the NIS, accusing the two organizations of being in “strange cohabitation.”

“The truth cannot be hidden by covering up lies with more lies. What else could the prosecution, which adopts unverified, forged evidence, do,” Han said.

The conservatives on the other hand are defending the prosecutors’ office and the spy agency, saying that the case concerns China’s counterintelligence activities.

Rep. Yoon Sang-hyun, deputy floor leader of the ruling Saenuri Party, has repeatedly stated that the case involves China’s counterintelligence policies, claiming that Beijing considers local officials providing information to foreign countries as espionage.

Yoon also implied that the Chinese Embassy in Seoul may have ulterior motives in saying that the concerned documents were forgeries.

The ruling party lawmaker also attacked the opposition bloc saying “politicians’ reckless sensationalism” was damaging national interests.

By Choi He-suk (cheesuk@heraldcorp.com)