Around this time, about 30 men dressed in long trench coats at Mount Inwang with winter hats, and black canvas shoes appeared. These people looked strange, even at first glance because as many as 30 people, not one or two, were moving in two rows. Their stiff expressions and fast footsteps, as well as the same attire, were enough to attract attention, even in the dark. They tried to pass through the checkpoint where two police officers were inspecting and rather yelled at the police asking for their identity, saying, "Don't interfere in our way. We are special forces returning from mountain training." However, the checkpoint they faced was on the road 300m ahead of the Blue House, and the two police, who found their words and actions strange, first contacted Jongno Police Station by radio. The chief, who brought his subordinates after receiving the message, immediately realizes that something is significantly wrong and instructs them to put them in handcuffs in an urgent voice. Just then, the No. 1813 bus departing from Gwanghwamun was coming towards them, and the bright headlights of the bus shone on the 31 people who claimed they were special forces members. But then what happened? They suddenly pulled guns out of their coats to shoot at the bus and started throwing grenades. On a peaceful Sunday night, passengers on the bus ended up facing an absurd death.