I have not been on forums about TP before, so perhaps this is old news, but in the series (the old one), they make a point of Leland not knowing that Bob is present right? That he doesn't remember what had happened when Bob was in possession of him?
When Leland goes after Maddy, she can tell it smells like something's burning, that would be the oil I presume. And Bob is obviously present. But at the hospital, when Jaques was murdered, there was the same smell, according to Jacoby. That would suggest that Bob was in the room? But Leland remembered all about that ...
I have seen the 4 hour video, recommended by this site, and the author of that meant that Leland probably wasn't totally unaware, they were more like in symbiosis with each other (is that how you say it?) That would explain my thoughts somewhat.
So, is this old news? Been discussed for 25 years perhaps lol. Sorry if that's the case, It was just something that I hadn't been thinking about before and I got real excited! =)
There are a lot of parts, but it starts here:
https://www.youtube.com/watch?v=9l0n_ZtxbH8
Doesn't seem that he forgets so much as loses control completely. BOB says that Leland is full of holes. Don't forget that Leland was grasping at straws in the show trying to find any way he could to frame someone else. It's never stated explicitly, but perhaps he thought that if he could kill Jacques Renault, maybe they'd pin the murder on the dead guy and call it a day. Regardless, BOB was definitely calling the proverbial shots for Leland, and so whatever logic the latter might have had as a human being is questionable at best by the time he kills Jacques.
In FWWM Leland shows the pages to Laura, saying "I thought you knew it was me" ( well at least she did when Bob allowed her to see it was Leland having sex with her. But she just took more drugs and tried to pretend it wasn't happening ), and then when she puts on the ring, Leland says "don't make me do this!" as Bob is going to kill her via Leland.