Slith reports the Guard are nearby - and they are indeed. One of the Guard approaches in a crouch and examines the ground.
"Fireball," he says, kneeling down running his fingers through the crisped soil, confirming everyone's suspicion. In the dark of the night the distinctive crimson of his outfit looks black. He also gazes out into the distance as if trying to determine from whence the spell came.
Slith, through his telepathic link to Sildarin, says, "There are three of them, all within about thirty feet of the edge of the blast. I don't see any more of them. Two are half-orcs, the one at the circle is human."