When the banquet and subsequently the assassination plot were postponed, Kim Jil lost his heart and betrayed the plot to his father-in-law, who reported to Sejo. The Six except Yu Seong-won, who committed suicide with his wife, were seized and tortured.
The postponement of the banquet and assassination plot led to Kim Jil betraying the plan to his father-in-law, who then informed Sejo.  Those six individuals, excluding Yu Seong-won who took his own life with his wife, were apprehended and subjected to torture.