There was an independent investigation and David Simon believes the evidence points to suicide unfortunately. I tend to agree. I didn't at first.

In the actual footage, Suiter sent the other detective to the other side of the alley. Suiter was pacing back and forth by the van for a while before running in the alley. Most likely contemplating the decision he'd have to make.

He died with his radio in his left hand and there was blood splatter inside the cuff of his sleeve. If he was murdered by his own gun after a struggle, that would all be implausible.

It wasn't a hit because his testimony wasn't gonna swing the case in any way. They had all they needed to lock everybody up.

But in his defense the angle you see in the show of him running in the alley is the actual angle from the footage. So from the show aspect it's still up for interpretation. Nobody saw the alleged person he struggled with

I wish they gave us 2 more episodes about the fallout of that. Police was treating Edmonson Avenue like it was occupied territory.