Who is the murderer of the ever-changing detective "Wedding Blessing"?

Ai Qi received a short message from an "unimportant private detective" and learned that her sister had died of Liu Tian's crime. I received a text message from Liu Tian and decided to kill Liu Tian. Because in order to understand the Song Dynasty, Ai Qi read all her books, including Wedding Blessing, and at the end of the book, she knew the death of the deceased, and planned to fake Liu Tian into a similar death to make him repent.

Extended data:

Yiqi put on Liu Tian's socks and let him sit at his desk. Aiqi stood behind Liu Tian, grabbed the fruit knife on the fruit stand next to her and cut Liu Tian's right carotid artery. Ai Qi didn't get blood because the blood in the carotid artery would spurt forward. Liu Tian first covered the artery with his right hand painfully, and then died on the operating table.

Ai Qi put the body in the shape of a book, and her hands were covered with blood. Then she remembered that the photo might be in her mobile phone, so she grabbed the ashtray in the room and smashed Liu Tian's mobile phone.