Lol no, guns don't just magically go off when in a holster. Yes mechanical failures do happen, but it requires very specific types of impact in very specific ways that cannot happen when in a holster and are so rare as to happen on decade timescales with tens of thousands of the gun. Also I saw zero evidence of that guys gun going off in the video, the first shot heard is the shot coming out of the ICE goon's gun that he is pointing at that guy, who then also mag dumps him while he is on the ground.

Well, that's an interesting take. Even if a holstered weapon did discharge (no idea how likely this is for the specific weapon in question), why would someone suspect they are being fired at by a person with a holstered weapon? Poor/no training is the most charitable explanation.

I suppose enough people will grasp at this take.

Has there been an investigation?

You saw the videos, the guy only had a phone in hand, he got tear gased, pinned to the ground, and then they unloaded their guns on him. Stop lying about what you saw, or we'll start to believe you're actually pro-murder.