I have recently been watching the series again. In episode 14, Cooper and the others go to the Hotel with Mike, who collapses and writhes about in agony when Ben Horne enters the room, smoking a cigar. Significantly, the cigar is lit: Fire, suggesting the presence of BOB. Perhaps BOB is possessing Ben Horne at this point, to throw the police off the scent! (They think Ben Horne has done the murder, not Leland Palmer.) Also, Ben Horne's reaction when the police come to arrest him is strangely animalistic and unlike his usual demeanour. He repeatedly and almost childishly shouts, "No! No! No!"

After Ben Horne has been arrested, perhaps BOB leaves Ben's body and enters Leland's body and carries out the murder of Maddy Ferguson.

In fact, BOB could have been alternately possessing both Leland and Ben Horne for many years. Perhaps he started possessing Ben from childhood...

Any thoughts about this?

It is made clear in the series and film that BOB's possession happens only if you invite him, he can't change vessels at will (he would have possessed Laura inmediately then, not try to force it). Leland comments how he appeared in his dream saying he wanted to play and that he went inside... BOB has been in Leland since he was a child.

Mike collapsing in the hotel when Ben enters probably happens for the same reason he points to the Great Northern a on the first place and why he says "BOB has been close" when Ben is next to him: Leland worked with Ben many years already possessed...and in the hotel...

That god damn trailer's more popular than Uncle's Day in a whorehouse!

Perhaps Ben Horne did allow BOB to possess him. Perhaps, when Ben Horne was still a child, BOB approached him and tricked him, in a similar manner to the way he tricked Leland. Then BOB was able to possess Ben at will throughout his life. In fact, he was able to alternate between Leland and Ben. This might account for Ben's corrupt behaviour, including burning the mill down, running One Eyed Jack's, extra-marital affairs, etc.

Having said that, after BOB effectively kills Leland and escapes, he never returns to Ben, so perhaps he is not able to possess Ben after all. (His next major target is Josie, and he feeds on her fear.) Perhaps Ben is too obvious a choice. The police already suspect that Ben may be connected with certain crimes. Perhaps, to throw them off the scent, BOB stays away from Ben, and instead concentrates on Josie.

Just a thought...

Perhaps, perhaps ... perhaps Bob is responsible for the fall of Tibet. Just a thought.

Beauty is momentary in the mind -
The fitful tracing of a portal;
But in the flesh it is immortal.
The body dies; the body's beauty lives.
So evenings die, in their green going,
A wave, interminably flowing.
So gardens die, their meek breath scenting
the cowl of winter, done repenting.
So maidens die, to the auroral
Celebration of a maiden's choral.
Susanna's music touched the bawdy strings
Of those white elders; but, escaping,
Left only Death's ironic scraping.
Now in its immortality, it plays
On the clear viol of her memory,
And makes a constant sacrement of praise.

('Peter Quince at the Clavier' by Wallace Stevens)

I just finished watching TP all the way through for the third time.

 Isn't it possible that Mike really wasn't leading them to the Great Northern? He described that Bob was "in a place with many souls, who enter and leave often" or something like that. Umm... can't that possibly describe the Black Lodge, where Bob truly resides?

He surely describes the Black Lodge, a place with many lost souls and doppelgangers, surrounded by sicomore trees and with many identical rooms, in which Cooper runs losting hymself trying to escape his doppelganger that follows him. In my opinion, the one-armed man collapses in the hall of the Great Northern because he was in a bad trip, without medicine for too much time...The entering of Ben Horne is only an accidental case...

 Sonia

Mike's poem about "a large wooden house surrounded by trees..." is ambiguous, and I think perhaps bothe interpretations are equally valid. There is an ambiguity is Mike's response, that allows it to refer to two things at once, two clues for the price of one...

(1) BOB is currently at the Great Northern possessing Leland and/or Ben

(2) BOB's ultimate dwelling place and place of origin is the Black Lodge, where "the rooms are each alike..."