[Demidog]

If for instance his trigger was of the variety that required constant pressure in order to remain unactivated that wouldn't be smart.

[wattsmag2]

It would have been obvious that that was not the case as he was uing a firearm with both hands.

[wattsmag2]

Regardless of what "trigger" the perp might have had, you have no idea(or at least none presented here) whether there was any continuing danger from this killer.