Circle S01 E06 The Chairman

In part 1, While digging for clues, Woo Jin finds a picture of Professor Han and his dad standing in front of Eunsung Psychiatric Hospital. In part 2, Beom Gyun meets Dong Geon. From him, he hears that the person who gave the presentation about the calming care system in the past was in his twenties, and he suspects that the chairman may be Woo Jin.