A National Intelligence Service agent and a collaborator were indicted Monday as a probe into allegations of evidence forgery neared its end.

The NIS agent and the collaborator, both surnamed Kim, are accused of forging the document supposedly issued by the customs authorities in the Chinese city of Sanhe.

The document is one of three allegedly forged pieces of evidence submitted by the prosecution to appeal Yoo Woo-seong’s acquittal in the ongoing espionage case. The spy agency official is also suspected of having been involved in obtaining all three fabricated documents.

Yoo, a former Seoul City official of North Korean-Chinese decent, is accused of handing over confidential information regarding about 200 Seoul City officials to Pyongyang. Yoo is also under investigation for allegedly committing fraud in receiving government subsidies for North Korean defectors and in gaining the Seoul City job.

Although the prosecutors’ office is reportedly planning to wrap up the investigation as early as this week, concerns have been raised about the effectiveness of the probe.

NIS officials questioned in connection with the case are said to have consistently denied any knowledge of the events, while the two indicted individuals have given conflicting accounts.

The NIS collaborator has testified that he was ordered to obtain the documents in question and that the spy agency was aware of all related developments. The NIS agent, however, has denied all allegations, saying that the collaborator had acted alone.

In addition, the investigators’ efforts to determine whether high-level NIS officials were involved ran into a roadblock following the suicide attempt of another key suspect.

The suspect in question is a midlevel NIS agent identified by the surname Kwon who was serving as the deputy consul general of the South Korean diplomatic mission in Shenyang, China.

The prosecution is said to be considering indicting Kwon, along with another NIS agent stationed at the Shenyang mission identified as Lee.

Kwon attempted suicide after being questioned for the third time. Although he has since regained consciousness, he is said to have sustained extensive brain damage that may have affected his memory.

As the investigators wrap up the case amid accusations of conducting an incomplete probe, the prosecutors’ office appears likely to come under fire for decisions by prosecutors involved in the developments.

According to reports, the prosecution is likely to subject the two prosecutors accused of misleading the court to bring about an internal audit rather than a formal investigation.

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