Invisible Killer

From publisher blurb: A series of vile murders have threatened the peace and prosperity of the quiet town of Harth. Unable to solve the murders on their own, the town’s Lord turns to the Adventurers to discover the assailant, and stop its murderous rampage. Will the Adventurers be able to find an invisible killer? Or will they reveal an even more dangerous threat hiding just beneath the town’s façade? Suggested party level: 3-4