Who really killed Ying Ying?

What happened to Ying Ying? Who was the real murderer? Until today, all I have are speculations. Honestly speaking, I have totally no idea how the case went and what were the results of the investigation. There did not seemed to be any outcome. It just ended abruptly.

OK, so he hung himself in the hospital, but did he do it? Why did he hang himself? Did he even do it? If she was not an accomplice and had nothing to do with it whatsoever, why did she lodge a false police report? Was a petty fine justifiable? Why was the false report not linked to the murder? Why did the investigation not go on? Did they have enough evidence to prove that he was the only person involved?

Why? Why? Why?

All these questions are still being left unanswered to me.

Personally, I question her credibility.

I have doubts… doubts…