It's a canny move, your attempt to focus the attention of your people on the possible cause of this death. Plus, it's true that the killer—man, woman or monster—may still be among you.
Only two low-level security guards are present, but they follow your instructions. One moves to block the building's main entrance; the other closes and locks a door behind reception that leads to a side exit from the building. Better yet, the rest of the people in the lobby allow them to do so without obstruction. They trust that you know what you're doing.
Next
Katariki was shot. He must have been. Nothing else could have caused such grotesque injury. You glance around the lobby: there are no open doors, no broken windows, no perforated walls.
The shot must have come from inside this room, yet you see no weapon, no obvious killer.
As you consider this, Brett Golightly and eight armed field agents arrive in the lobby. They fan out around the room, searching for any threat.
"Katariki has been shot and killed," you tell Brett, as he kneels down to inspect Katariki's corpse. "The killer is here somewhere."
And then, with impressive rapidity, one of Brett's team approaches and says, "We've found a bullet, lodged in the wall behind the receptionist's desk." He points toward the spot. It's down low, near the ground.