Gex frowns, "there are ways to mask a magical aura, I would treat that staff with the utmost care and have it inspected a little more through than a simple cantrip." he looks to everyone else, finally realizing they were still covered in the gruesome goop "Does anyone else need help cleaning?" he asks earnestly.
If the sergeant isn't interested: "Well, I'll take the staff then, how much?" he asks the seller.
Spoiler
Offering Prestidigation, if not, he'll clean up any remaining in the area.
Gex
HP's: 16/16
AC: 16
Class DC: 17
Speed: 25ft
Fort: +5
Ref: +6
Will:+5
Perception: +3
Feats: Hobnobber, Unexpected Shift
Effects: none