As of Episode 03

1. The CEO. He wants to drop him because he's becoming a headache. He's willing to risk the drop in share prices because he expected it to be closed fast. Unfortunately for him, there's a fierce attorney who's prolonging it.
2. The Manager. Out of all the people around him, he's probably the one who's most angry since he's the one who has to endure everything.
3. One of the staff. Three of them did say they want to kill him and were holding pointed objects.
4. The father(?) of the prosecutor. As he said, their job is to pick a suspect and force them to confess regardless if the confession is true or not. He probably heard the comments of the disgruntled staff and so he set the ML up.
5. The father of the ex-girlfriend. They haven't shown him yet but since they're wealthy, her father probably hated that they were dating. He was probably the reason why they broke up.
6. That angry band member, the drummer IIRC. The victim didn't struggle, as the police said, the victim knew the suspect. And since the victim is also intoxicated, more reason he wouldn't think the suspect would actually stab him.

Why I think the ex-gf is not the suspect:

• She was paying attention to the case.
• She studied the profile of the prosecutor.
• She met the prosecutor pretending to be interested in him, but she was actually fishing for information at the same time planting doubt and leading him to other possible scenarios.

However, I suspect that she knows something. She probably knew who the suspect was but she's too afraid to share the information with anyone because she'll get dragged into it.

Again, only up to E03 as of the time of this writing.

my bet is for the manager. i think least people will have suspicion on him

 Ivy:

I'm assuming La Ik was the actual target so I'm ruling out anyone with open animosity towards him. Looks like the angry bandmate will be exonerated next week, we'll be focusing on what he knows. My money is on the younger bandmate right now or the manager.

Why do you think the younger, nicer bandmate did it? As I type that, I realize why I now think the younger, nicer bandmate could do it!! If his arm is permanently damaged; has nerve damage and he can't play the guitar anymore that could be motive and  Woo Sang would let him or the other member in if Ra Ik was in bed sleep. 

yeah, the mad band member look suspicious for us viewer, he even around the crime scene. But my bet he is not the killer, just distraction to us.

The CEO also probably a distraction.

because of you, now i remember too that the injured one said that he have nowhere else to go. Dang, i don't pay attention who said that.

We'll see in upcoming episode, how is his arm. Tbh, from the scenes we got so far, it little chance that his arm is disfunctional.

the maid played by a well known face, she probably will have more screentime, or bigger role. But she is not the killer.

I think it's possible that it's the CEO or the manager forced by CEO. In ep. 6 the manager shouted at Jae Hee something like "stop saying it's La-ik because it's not him!" so now I'm 100% sure that the manager knows who the real killer is. But still I think CEO / the manager may be too obvious choice, the CEO is already portrayed as a bad guy so we will suspect him

So right now my guess is that it's the father of the ex girlfriend. I think he's definitely entangled in the case, because he was pressuring the prosecutor's father to force his son to end the case quickly and make the story to be La-ik's fault. Why would he care so much about the case if he wasn't a part of it

 Sweet0Girl:

Why do you think the younger, nicer bandmate did it? As I type that, I realize why I now think the younger, nicer bandmate could do it!! If his arm is permanently damaged; has nerve damage and he can't play the guitar anymore that could be motive and  Woo Sang would let him or the other member in if Ra Ik was in bed sleep. 

To add on to this, since the drummer (angry) band member left the hospital, there is nobody left to confirm that the nicer band member's alibi is true.   

The CEO. Well I hope not the maknae of the band. But knowing Kdramas, it could be him. 

Episode 8

More information, more questions. I do think that ex is way too obsessive. Unhinged even.