Lilli_

As to your last point, it was Ba Reum who said that the box was only left unwatched while they were eating. But if he's the culprit, this could as well just have been a lie and he might have attacked his friend not during lunch but at a different time.

This is what they usually do when they're behind with filming. I was actually already concerned when there was no trailer last week, since that means they're live-shooting now. Going into live-shooting when the drama isn't even at the half point must be really straining for all the people involved in the production. I don't mind waiting for episodes if this means that the drama's quality won't decrease (even though the wait will be really hard haha).

The recent episodes aren't that good imo, you need to watch older episodes. I especially like the episodes that teach you meaningful stuff, like ep. 155 or 158 for example.

1.
I was wondering about this too, but then I found the possible motive for Ba Reum killing his friend. I'll repost my previous comment on this:
"There's one thing that bugged me if we suppose that Ba Reum is the cross killer. It was mentioned that psychopaths usually avoid killing people they're close to, so why did he try to murder his own friend? But after rewatching some parts of ep. 2, I found the possible motive. When Dong Goo expresses his fascination for Han Seo Joon, Chi Kook becomes enraged and shows his disgust for psychopaths with the following words: "Killing a weak, powerless woman after hiding like a rat. This cowardly bug-like bastard." I think these words could have easily provoked Ba Reum to choose Chi Kook as his victim. We have the symbol of the rat/mouse (the Korean word for rat and mouse is the same) here again, which I believe stands for Ba Reum himself. And Ba Reum is definitely intelligent enough to murder spontaneously and still not leave any traces even without planning a long time in advance."

As for the priest, I think he just happened to become his target because he was Moo Chi's brother, and Ba Reum was having fun playing with Moo Chi. As for Grandma, he never intended to kill her but had to since she got in his way. She sent Ba Reum a message saying she knows the face of the cross killer and wants to meet him. Ba Reum could easily have misunderstood the situation as her finding out that it's him and wanting to confront him about it. She also told him to meet up at a place where other people are (but the shop was closed in the end).

And last but not least, from the writer's perspective there's simply a lot more impact if he killed people that are closely related to him when he later starts to repent. He won't feel as bad if his victims were only random people he didn't know.

2.
I completely agree, the live broadcast episode actually made me think that it can't be Ba Reum after all back then (but I quickly changed my mind again after watching the following episodes). However, I actually saw a comment here that logically explained that very episode under the assumption that the cross killer is Ba Reum. I'll try to find that comment and repost it here.

3.
He was always in public spaces in those scenes. There could have been people in the background, or he just made it a habit to always pretend im public spaces whether there are people or not, since you can never be 100% sure that really nobody is watching. He's a highly intelligent perfectionist after all.

As for Bong Yi, we learned at the beginning of the drama that psychopaths have a high interest in reproducing. I think Bong Yi was his target for that purpose. He probably thought she'd be an easy prey, poor, only a grandma as her family, etc.

And as for Ba Reum bringing the noodles to Moo Chi and being happy that he ate them, I think it's because Moo Chi was his favorite "toy" and he'd need to "revive" him first so that he could continue playing with him.

There is no concrete proof that it was Yo Han. It's all just assumptions. He was never shown doing the murders, we only saw that he was at the scene as well in some cases, but this isn't enough to say that the culprit could only have been him. Same for the childhood flashbacks, it was never shown that they're Yo Han's. We still don't know for sure who Jae Hoon is.

The sudden rise is strange, but I like it haha. So far, this drama totally deserves such a high rating. 8.5 was too low imo.

I found it pretty absurd as well at first, but they might argue that he's been a model prisoner for the past 26 years and thus let him free. Apparently stuff like this does happen in real life, someone posted the link to an article about cases like this somewhere below.

https://www.youtube.com/watch?v=1fEooeJjvWk

Why would you say so? I didn't see anything in the preview that confirms brain transplant.

It was clearly shown that he kills it.

It's impossible since the bird scene proved Ba Reum's killer instincts. He had just woken up and didn't have any memories at all at the time and thus he killed the bird by pure instinct. His memories only started to resurface afterwards, so they can't have influenced his behavior in the bird scene.

This is indeed a very interesting theory. But it doesn't explain why Ba Reum would have killer instincts.

He was a genius who did his own private investigation into Ba Reum, and he was several steps ahead of the police. He must have developed extreme hatred for psychopathic serial killers after being associated with Han Seo Joon all his life, which is why he was out to kill the cross killer (just like how Moo Chi wants to kill Han Seo Joon). I think it will turn out to be something along these lines.

He clearly showed feelings like fear and sadness, so he can't be a psychopath.

That would make sense.

On the contrary, I actually saw an interview in which he said he's nervous about the feedback since his character is so different from his usual image. Which would speak for him being the killer.

Oh really? I haven't heard of such an interview. If you find the link to the alleged interview, please let me know.

I highly doubt Lee Seung Gi would reveal that, the interview is probably just a rumor. Or something he said was taken out of context and/or misunderstood.

She's not a high school student anymore, there was a time skip. She's 20 and he 26. I personally see no problem here.

Oh wow, thanks for the link!

But now I do wonder, what could be the writer's purpose of setting Han Seo Joon free? To make it impossible for Moo Chi to kill Han Seo Joon, since once Moo Chi goes to jail, Han Seo Joon will be out? Or Moo Chi won't end up in jail in the first place because Han Seo Joon will be freed before Moo Chi will be convicted and thus Moo Chi will reveal the truth that he didn't kill the detective?

Moo Chi told Han Seo Joon before that he's going to come to jail to kill him. So what Han Seo Joon is saying in the trailer refers to that. He's going to wipe his neck as in preparing to get killed by Moo Chi since the latter is about to come to jail. Han Seo Joon probably saw on TV or in the newspaper that Moo Chi is being accused of having killed the old detective.

Oh and I just realized after rewatching that the lawyer seems to be tailing Ba Reum.

But why? Did he recognize Ba Reum as a psychopath? But Ba Reum's eyes have changed, so that can't be it. Did he know Ba Reum already before the surgery? Did he actually try to get close to him for whatever reason might be and thus also befriended Dong Goo?