Killing Grunts/Brutes question

[The Rock Worm]

I have read that, other than making them (basically) fall down a cliff and die, the player can't kill a Grunt or Brute. My question is, if one made a custom map with a Grunt walking towards a water pit with a Kaernk in the water, will the Kaernk attack and/or kill a Grunt?

In the game, the Kaernk (or Water Horror) goes after anything it detects in the water. It could be a player or a bit of meat thrown in the water. I figured that, if a Grunt walked into the water, wouldn't the Kaernk go after it?