This may actually be an Errata request. But I'm noting that the Detective is using a Riot Grenade Mk 3. All the other NPCs with this Riot Grenade refers to it as the Riot Grenade III.
The reason I make this distinction is that the Detective's grenade is missing the damage listed in the Armory entry it's from, which refers to it as III.
The only place I find it referred to as Mk 3, is AonSRD. And their damages for the Riot Grenades seems to be shifted.