Familiars: Empathic Link (Su): The master has an empathic link with his familiar out to a distance of up to 1 mile. The master cannot see through the familiar’s eyes, but they can communicate empathically. Because of the limited nature of the link, only general emotional content can be communicated
Familiars are often problematic in this regard. While Louie could swoop out and find the fleeing assassin, I don't think 'general emotional content' would include whereabouts precise enough to enable the effective casting of glitterdust. However, it seems only natural that there would be some chance of success. A listen check of 5 is required to hear Toler running when he starts. It takes a full round for Beamer to get up to the top off the wall, on banions's back. Toler can't see in the dark, so let's say he only moves 30 feet/round, picking his way into the trees. So if Beamer can make his listen check at 10 over the minimum (which would be 8), he can hear pretty close to where Toler is. So he should make a listen check at DC 18.
Success! Thus Beamer tags Toler with his glitterdust. Boog, then, can see him, an cast mind lock.
Toler gets two will saves, vs glitterdust and brainlock. Unfortunately for you,
he makes both. the Glitterdust description doesn't state this directly, but I'll assume you can now see him in the dark for the duration of the spell.
Toler, in turn, increases his speed, dashing East towards the Silverwood, which abutts the small fort. I'll require a Balance check of DC 12 to avoid tripping on bushes and rutts in the dark if he's running.
He makes it. Thus he moves 120 feet, and disapears into the scattered trees and bushes to the East. He's now approximately 150 feet away from Beamer, and about 200 feet away from Boog. Even with the glitterdust, he is difficult to see through the trees. It is currently late november, and there are no leaves left on the trees. Most of the trees are deciduous, so the PCs still have a chance of spotting him. Spot check DC20, +1/10 feet -40 for glitterdust spell...OK. I guess both PCs can still see him at this point.
Eusebius checks Bill's body. He has no life left in him. The monk/cleric can see that the thrust went directly into his heart. Either Toler was lucky, or he is skilled at attacking unsuspecting foes.
Juliana has one more round on the winch to get the gate closed.