Last time I looked, that's not clear, actually. That he manually cycled the action could be indicative of a bolt-action pistol, OR it could be indicative of subsonic rounds or a heavy suppressor with a non-modified action. Basically adding weight to the weapon or reducing recoil makes it harder for the gas-operated action to automatically cycle, so you have to cycle manually.

Are we sure of the weapon type?

I've heard that there was live ammunition recovered at the scene, and that basically means the action was manually cycled to clear a jammed round.

At this point it's hard to rule out a janky weapon with homemade suppressor, or a rare specialized weapon as you suggest.