A former student who was found not guilty of aiding and abetting the suicide of a fellow activist demanded an apology from the judiciary Monday.

In 1991, Kang Ki-hoon was convicted of ghostwriting the will of Kim Ki-sul and persuading him to set himself on fire and jump to his death from a building at Seoul's Sogang University in protest against the then authoritarian government.

In a retrial Thursday, the Supreme Court upheld Kang's acquittal, citing the lack of credibility of forensic evidence.

"Prosecutors handling the case at the time distorted the truth even though knowing that I did not write the will," said Kang through Minbyun, a society of lawyers defending his case, in a press release.

"It is time to accept a mistake and offer an apology," Kang said.

Often called the Korean version of France's "Dreyfus affair," the self-immolation by Kim in May 1991 came amid nationwide protests demanding the resignation of then-President Roh Tae-woo. The incident played a role in worsening public sentiment against student radicals.

After serving three years in prison, Kang sought a retrial.

"The court should offer a word of apology," Kang said, hinting he may take legal action.

The Truth and Reconciliation Commission, a special committee established in 2005 to reinvestigate past security-related cases, ruled in 2007 that the prosecutors pinned false charges against Kang. (Yonhap)