He knows!

Soon one of the guards said, "Two of the guards were knocked out today near the dungeon and we found this stuck in the lock of the back door of the dungeon." 

The man let out Chao Xing's pin and held it in front of him with both hands. 

Chao Xing's eyes widened seeing that, 'How can I forget about this?' 

She wanted to slap herself for the thing she did. 

Wen Ting Hua pushed his hand forward as he pointed towards the man to bring him the pin. As soon as the man got permission to come to him he stood up from the floor still with head bowed down. 

Putting the pin on the table he again bowed down his head and took some steps backwards still with his head bowed down. 

Wen Ting Hua grabbed the pin which was kept on his table and started analyzing it. 

"Someone tried to open the door and get inside the dungeon. This pin is of a noble maid so there are chances it was one of your maids." The man explained after going back to his place.