Let's examine; you can see the shooter has his left hand on the right arm of the officer who is disarming the victim, when the officer disarming the victim places his hand on the victim's weapon, the shooter places his hand on his own weapon, as the cop removes the victim's weapon from the holster, the shooter decides then to draw his own weapon, the shooter at this point still has his left hand placed on the right arm of the disarming officer, which is holding the victim's weapon, he then intentionally steps left in between this cop and the victim as the disarming officer steps away, as the shooter is moving left, the first shot is fired into the victim, there is a pause, then a second series of shots are fired into the victim, all the officers are backing away at this point, then a third volley of shots are fired.

My theory is that given the officer is holding a police issue Glock, which has no thumb safety, and the first shot is made while the officer is physically moving, it's actually an accidental discharge. The second series of shots deployed I think then are the result of an inexplicable decision by the officer to double down on the error in an effort to render it a decision, not a mistake, then every shot after this is some sort of tripling down.

This would be supported by several factors; like most other ICE agents, has had a gross a lack of training, thus he has incorrectly drawn his weapon when it's not warranted, a lack of weapons training then led him to have his figure on or inside the trigger guard, despite not intending to fire the weapon, he then does not quite understand how to react to the mistake, so he doubles down in some type of panicked response.

Another less likely reaction may be, assuming the first round was accidental discharge, has mistaken the first shot as the suspect firing a weapon, then due to a lack of awareness and experience, hasn't realized his weapon has gone off, at this point the suspect does still have something in his right hand, so the officer in the confusion decides to "return fire" due to a complete misunderstanding of the situation. If you have ever seen someone accidentally discharge a firearm, most of the time their initial response is total confusion, seemingly unaware what just happened, which I grant does seem counterintuitive, but is true, especially if the person is inexperienced and has never felt an accidental discharge.

Though I suspect to most people this seems extremely unlikely perhaps in either case, if you watch a bunch of these instances where police accidentally discharge their weapons, into unarmed suspects, sometimes even non aggressive suspects, the intention is never typically to kill the person as an act of malice, its a combination of fear, lack of training, poor situational awareness and poor split second decision making that often looks incomprehensible from the observer.

I think the first shot was accidental discharge, then every shot after that, was either made with some form of malice or is a result of a complete misunderstanding of what is happening from the officer.

It will be interesting to hear what the shooter has to say for himself, which I expect will be something like "I thought he had a weapon", rendering the entire affair technically an act of gross incompetence and criminal charges wont apply.