Emperor Yue could not trust anyone at this moment, so he assigned the investigation to Han Zhao!
Han Zhao was accustomed to witnessing the dirty affairs within the palace and had authority over all the palace servants, big and small.
Emperor Yue had made up his mind to clear up the matter today, so he simply sat in the outer chair and watched how Han Zhao conducted the interrogation.
The urgent task was to find out how exactly the little prince had come into contact with the egg.
The Imperial Physician had carefully confirmed with Ouyang Jing that there were supposed to be no egg products in the King Fu Residence, and Ouyang Jing was extremely cautious with her own diet.
Moreover, Ouyang Jing had breastfed the little prince two hours earlier, and if there had been an issue with her diet, the little prince would have shown a reaction much earlier, not just now.
Thus, it must have occurred after entering the palace.