The Investigators are a pair of radio-controlled (and, incidentally, rather lethal) sculptures created by the ex-convict Slick Henry in Mona Lisa Overdrive. The Investigators were originally designed as remote control devices to be used in nuclear power plants, chemical cleanup operations or various other very hazardous environments. They are about the size of a large motorbike. Slick first built the frames from three unassembled kits he found in Newark, trading a Volkswagen for them. Now, instead of grippers and manipulators, each Investigator packs a pair of sharp claws with mounted flame thrower, plus a thermite lance on an extendable scorpion-tail.

The Investigators were Slick's penultimate creations, after the Witch and the Corpsegrinder, and before the Judge. Near the end of Mona Lisa Overdrive, one of the Investigators is used by Gentry to first disable then torch a heavily armoured hovercraft.