Do Circles Radiate a Magical Aura?

[Green Eyed Liar]

I am running a module, and there is an accuser devil held hostage by a summoning circle. After the encounter, the monster is gone and the party wizard casts Detect Magic. Would the now empty summoning circle have a magical aura? If so, what school of magic?

[Val'bryn2]

Is it a permanent spell holding the devil or a one-off? How quickly does the wizard cast it?

[Green Eyed Liar]

It was cast days prior to its discovery. The module does not go into details about its nature or what spell, only that it contains the accuser devil. I think it works like a Magic Circle Against Evil, even though that particular spell is never mentioned anywhere.

[PrinceRaven]

Assuming they didn't break the magic circle it should still be active and have 2 abjuration auras; one faint aura for the magic circle, one moderate aura for the dimensional anchor effect (there has to be one as accuser devils can teleport). If they did break the circle the auras linger for 1d6 rounds for the faint aura and 1d6 minutes for the dimensional anchor.

[Pizza Lord]

It would also have an aura of good if it were a magic circle against evil because that is a good spell (I am just assuming, if it were of a different type it may have a different alignment aura). I don't think the alignment auras seem to leave lingering auras, unlike magical ones, but you could allow a dim alignment detection in the case of spells, your call.

Obviously the detect magic the wizard cast won't pick any of this up, a detect good or similar spell would be needed. I only mention it for completeness sake on auras.