I'm not commenting on the circumstances of this case, however it's being investigated because the killing of any griz, (a federal endangered species) requires an inquiry to see if the killing was justified. Griz are killed in Montana every year, guys shooting them thinking they're black bears, ranchers kill them for attacking livestock, several are killed every hunting season in reported self defense shootings, and some guys shoot them out of pure damn meaness and let them rot. One of the biggest grizzlys ever studied was shot and left to rot last year for no discernable reason, matter of fact they found several like that last year.
They have to make sure the killing wasn't an over reaction, people shooting when it really wasn't necessary, griz will bluff charge and challenge you, and of course, sometimes they charge for real.
I'm glad the hikers are ok, but also hope the griz didn't die for no reason, I like having them around, means you still live in a wild state,
Take care...