There was no premeditation so it wasn't murder.
The officer that drew his gun and fired was initially focused on the arrest of the lady who was struggling on the ground near Pretti. IMPORTANTLY, the officer had something
white in his right hand, which might have been mace?
Once it seems like the lady is subdued, the officer slowly turns around towards Pretti, who is struggling mightily. While the officer was capping the mace and putting it away somebody yells "He's got a gun!"
five times, and the officer with the mace fumbles for a second, and
only then draws his pistol. After that, the yeller yells "Gun! Gun! Gun!"
The armed officer then pushes the officer who got Pretti's gun out of his way, and is repositioning to Pretti's left side. It seems like the first shot might have been accidental because the officer visibly jumps when the shot goes off. After the first shot, there is a pause where Alex Pretti sits up into a kneeling position, and his right hand goes towards his waistband holster. Maybe he was reaching for his injury and not his gun, but that movement seems to have prompted the remaining shots from the armed officer.
SUMMARY: I don't think the officer went into this scuffle intending to shoot anybody. He was actually calmy putting the cap on his mace when Pretti's weapon was discovered. After the officer drew his weapon, his first shot seems to have caught him off guard. After that first shot, he didn't unload his weapon until Pretti motioned towards his waist band. That means he may have reasonably thought his life and that of everyone around them was in danger.
This is the video I'm referencing:
Please respond with FACTS AND ANALYSIS ONLY not emotionally or politically driven comments.
If you think some of my facts are wrong, please point that out in a calm and civil way.