The next questioning is with Lin Meng Yu, the real estate agent. He confirms that Mei Bao and Boa Luo were friends and he never saw Da Sen with Mei Bao. Dusting the apartment reveals no fingerprints. Officer Yang finds out that Lin Meng Yu has the keys to many of the apartments and can go in and out without the knowledge of the owners. Detective Zhong talks to Ding Xiao Ling from 23rd floor who used to be Meng Yu's mistress. The two of them snuck into apartments and roleplayed. Meng Yu also reveals that Mrs. Lin is the one who bought unit 2003, not her husband. Per Yang's suggestion, the forensics dust the ventilation duct and find two different fingerprints there. One of the fingerprints belongs to Lin Meng Yu. Also, a year before, during new year's eve, a housekeeper was exposed as a human trafficker and arrested. (Source: Autumn carrot at MyDramaList)