It's always such a pleasure to discover new things in Twin Peaks, especially considering its been around for almost 20 years and I've seen the series close to ten times now. My husband and I have started viewing it again (my eight or ninth, his second) and he noticed something kind of cool in episode 4 during the scene where Sarah is describing her vision to Harry and them. As she's describing the person we soon learn is BOB, she gets very upset and scream "That FACE! That FACE!" or something..something about his face. At the very second Sarah screams this, it cuts to Leland standing there, looking annoyed. He then speaks angrily about Sarah's visions.

 Maybe we're making a mountain ut of a mole hole, but I find this discovery to be pretty interesting. With the hindsight we now have, it's a very poignant moment!

I'm rewatching the series again and been a little puzzled about some scenes where it seems that the writers & directors knew about Leland from the beginning. It's gotta be that "air of mystery for everyone", keeping each character under suspicion, but in some of Leland's scenes it just seems SO obvious. Strange...

"What credit card do you want to put that on?"
"Caash, prease."

That scene in ep 2 has several indicators.

1. It opens with Leland snapping his fingers over the victrola.  The episode ends, after the dream sequence, with Cooper doing the same.
2. Sarah screams "Leland, what is going on in this house," which has a creepy air to it once you know the extent of what HAS been going on in the house.
3. Leland's jacket has an unusually large harringbone pattern that is very visually similar to the red room floor.
4. The image of Leland standing over his daughter's picture with blood all over it and himself is also a somewhat of a visual cue.

Another that comes to mind is the coffin "humping" in episode 3's funeral scene when Sarah says "don't ruin this too!"  There are probably more, but that's all I got for now.

So, do you think that Lynch/Frost knew that Leland was the killer?

Or, maybe it just seemed right after the aforementioned scenes had been filmed.

"What credit card do you want to put that on?"
"Caash, prease."

Lynch & Frost had decided from the start that Leland is the killer, ain't that a fact?

 What I originally meant was I thought I got the feeling that some of the other writers & directors also knew this. And we've been told that was NOT the case, that only Lynch & Frost knew the secret. I'd have to check all the season 1 episodes again to point out the scenes I mean...

Episode 3
Director: Tina Rathborne
Writer: Harley Peyton

But Frost or even Lynch probably had something to do with the funeral. Apart from that, I think it's telling that the most obvious hints came in the Lynch-directed episode.

"What credit card do you want to put that on?"
"Caash, prease."

I think it is notable that Leland is aggravated when Sarah tells them about the necklace/BOB. What happened to his grief?

 Also, in the pilot there's *subtle* clues. Hawk is taking the contents out of Laura's room and when he takes the diary Leland says "do you really have to take that?" Leland examining Laura's corpse might be another one as Dr. Hayward asks him if he really wants to see it (implying that normally a grieving father wouldn't). Of course they laid other red herring clues (Pilot- Audrey Horne's blank expression at the announcement of Laura's death; episode 1- Plastic all around Leo's house- this one is interesting, because in the 8th episode script there's a line that goes "the third man then wrapped Laura in plastic from Leo Johnson's house." I don't recall the line in the actual episode; episode 3- Ben Horne hovering over Laura's body himself- the scene starts with that shot).

Episode 2, Maddy making her entrance.

I love this scene. Didn't notice, despite watching it probably 25 times, before someone here pointed it out. 

Jade(Invitation to Love):"Daddy? It's Jade."

Maddy: "Uncle Leland?"

Jade:"Daddy. please. I know you're in there"

Leland:"Madeleine?"

Jared(Invitation to Love):"Jade. What a surprise"

Leland:"Maddy? Is it you?"

Cleary, Lynch early on gave some hints to the viewers the Leland definitaly had some sort of special relationship to Laura. Sarah is naturally crushed after her daughters death, but Leland reaction is somewhat something far more.

"What credit card do you want to put that on?"
"Caash, prease."

I see it, but it really is in hindsight -Ray Wise didn't act those scene with knowledge he was the killer, and even if he wasn't revealed to be the murderer, those early scenes would still work, still had truth of grief.

If Audrey was unmasked as the killer, we'd say the signs were there -cold, distant, smirking in the classroom, "knew Laura better than the others," danced compulsively like the little man, "there's always music in the air."

Donna wants Audrey, maddy and James to keep what they find out "to themselves."

Dr. Hayward in the second episode when revealing her autopsy couldn't do it himself, so brought someone else in -obvious guilt from killing her?

the signs and clues were there for most of the people -it's funny at the time, I never even thought about the Palmers because I didn't feel like they were major characters.

But this is the strength of the first half of the series -everyone is a suspect, and a plausable one.

Good question.

No, I don't think they did. And believe that the footage they had filmed led them to 'the killer'. 

"What credit card do you want to put that on?"
"Caash, prease."

Yeah, maybe.

I recall in the extras of the Gold Box Edition Mark Frost says something like... "...we kinda knew who the killer was."

I always kind of figured somewhere around the middle of Season 1 they really started to 'narrow it down'.

That said, I was always suspicious of the scene in the Pilot Episode where Sheriff Trueman turns up when Leland receives a call from Sarah, who is obviously aware of something bad happening, to tell him Laura has been murdered.

That's what I loved about the show though. It seemed almost improvised at times and yet they found a way to tie it all together.

Fairly certain about that Frost comment. I will check that again though.

Yeah, that could very well be the case.

What comes to Lynch & Frost deciding about the killer, I believe they knew from the start that they were making a story that has father who abused & killed his daughter, and the crazy idea of inhabiting spirit was there too. They just didn't know yet how to exactly play it out. Then, while shooting the pilot, Lynch got the idea of Bob, and the whole thing developed as they went on.