A South Korean intelligence official has attempted suicide a day after being questioned by prosecutors over his alleged role in forging Chinese government documents to frame a North Korean defector for espionage, police officials said Monday.

The 51-year-old mid-ranking official at the National Intelligence Service, only identified by his family name Kwon, is in critical condition at a Seoul hospital, according to the officials.

Kwon was found unconscious inside a car near a middle school in Hanam city, outside of Seoul, around 1:33 p.m. on Saturday, according to police.

Kwon, who was rushed to a nearby hospital for treatment after being discovered by another driver, was again transferred to the intensive care unit at the general hospital in southern Seoul, the officials said. 

The deputy consul at the South Korean Consulate General in the northern Chinese city of Shenyang returned home after undergoing questioning by Seoul prosecutors on Friday over his involvement in the alleged forgery case.

The case first began when prosecutors indicted Yoo Woo-seong, a 34-year-old defector in South Korea with a Chinese ethnic background, on charges of carrying out espionage activities for Pyongyang's spy agency. 

Prosecutors alleged that Yoo relayed a list of North Koreans who defected to the South and their personal information while he was working for the Seoul municipal government.

A local court, however, acquitted Yoo of the espionage charges in August 2013, and allegations have risen that the NIS used fake immigration documents and other key documents issued by Chinese authorities to bring the espionage case against Yoo.

The Seoul Central District Prosecutors' Office probing the case suspects that Kwon is deeply involved in obtaining the documents that were later announced by the Chinese Embassy here as fake. (Yonhap)