The U.S. State Department recently declassified documents regarding the terrorist attack on Korean Air Flight (KAL) 858 in November 1987 that appear to confirm that the explosion was the result of a bomb planted by North Korean agents.

The documents detail the U.S. government’s own investigation into the crash, including the arrest and trial of Kim Hyon Hui, who confessed to being a North Korean agent and conducting the mid-air bombing of the jet that killed all 115 on board.

Kim was arrested with a second North Korean male in Bahrain, after the two were caught carrying false Japanese passports. They quickly became suspects in the case due to having left flight KAL 858 just one stop before it disappeared from radars.

“The two reportedly attempted suicide by swallowing cyanide capsules concealed in cigarettes. One, a male, died as a result,” one State Department cable explained.

A later cable also explained that through early access to the South Korean government’s interrogation findings and discussions with other diplomats, U.S. officials found the Korean investigators’ case to be credible. One diplomat wrote, “I reviewed a translation of the documented case and it appeared to be a very carefully developed study.”

Kim later went on TV to express her remorse for planting the explosive device on KAL 858, saying she had “watched ROK TV and realized that she had been misled by DPRK authorities about the situation in South Korea.”

A further cable confirmed that the Korean investigation found she was acting under “Kim Jong-Il’s instruction of blowing out Korean Air passenger planes in an attempt to discourage other nations from participating in the 1988 Seoul Olympics. It was also disclosed that the instruction was given in Kim Jong Il’s own handwriting.”

Also included in the State Department’s release are cables that detail the U.S. government’s eventual decision in January 1988 to put North Korea on the list of state sponsors of terrorism and apply further sanctions pursuant to the bombing.

Even today, despite the body of evidence to the contrary, the incident is still controversial in South Korea, with some claiming that the Chun Doo Hwan military dictatorship of the day fabricated it so as to influence the December 1987 elections.