Kemp explains to Adye that they have to take measures against Griffin because he's insane, a person of "pure selfishness" (25.2).
They have some advantages, though. For one thing, they know that Griffin wants to get to Marvel and his stolen books.
Also, Griffin basically told Kemp his life story, so they have all that information. Kemp knows that they can keep him unstable by making sure he doesn't get a moment to eat or sleep. And of course, he knows that they can use dogs against Griffin.
Kemp even suggests that they put powdered glass on the roads, but Adye objects that "[i]t's unsportsmanlike" (25.17). At least someone's worried about that.
Kemp counters that Griffin is inhuman, that "[h]e has cut himself off from his kind. His blood be upon his own head" (25.18). Man, we wish we could think of a joke to put here, but this is dark.