More likely:
At some point LEO will simply idly stand by and watch these events unfold...only to get involved as witnesses to document the mayhem after all the killing is done.
This is plausible. I know the circumstances pale in comparison, but I have a story along these lines.
During my years of high school teaching, there were two girls who were constantly jawing at each other. A constant low-grade disruption. It never ended. I observed them in the cafeteria one day, and it looked like it would come to blows. So, I didn't do anything. Just kept watching them till one threw a punch. And still I waited for the other to retaliate. Only then did I "realize" that a fight had broken out! Oh, no!
Afterwards, it was haul them to the principal, tell what happened, have him review the video, and TA-DA! Instant suspension for both.