anyone who has read the raws and understand what will happens at the end, please spoiler m...

Kang Moo did it to protect lee kirin. Because that profiler will not give up until they have someone to blame. And close the police investigation.
That guy loves lee kirin in his own way.

so they are ended together as happy ending...?

OMG A BIG THANKS FOR YOUDUDEEEEE THIS IS A WHOLE THAT I NEED FOR REALLLLL┗( T﹏T )┛thankieeeeeee

Thank you so much!!

Damn u really put in so much more effort. Thank u sm

I knew it! They don't really break up but Moo wants to protect Kirin in his own way! He loves Kirin , finally Kirin realize too that he loves Moo. Thank you so much for this spoiler

I like your break down but I have different opinion on current story line. I believe the breakup was legit. I think this new development with the involvement of the forensics guy has made him realize that Kirin has become a hindrance and needs to break that off. It’s not so much for Kirin’s protection as it is more about his own preservation, so, he will try (and fail) to part ways from Kirin. I’ve also “read” the raws a few times and now am (im)patiently waiting every Tuesday for the Lezhin release, and the authors comment on Twitter regarding the English translation/interpretation.
The only slight difference of opinion might have to be regarding the case that triggers his psychopathic nature. Yes he asks Kirin to move but bf and after that particular convo, he does harm Kirin , one of the times severely injuring his neck. So yes while it is a get away before i kill scenario, it isn’t without incident. But true like you said Kirin was like on that plan, I’ve seen the dark side and it ain’t half bad, maybe a little chilly.