I see some speculation going on, as to whether the victim was in some way connected to the killer. The victim (Robert Godwin, Sr.) was definitely just a random man, in the wrong place at the wrong time, just walking down the street carrying a plastic shopping bag, like he's just been to the store. Here are details from that terrible video (available on this Heavy web page) :

Stephens is driving his car down a street.

Stephens: Found me somebody, somebody I'm about to kill, I'm gonna kill this guy right here. He's a old dude.

Then Stephens pulls his car over, gets out, approaches Godwin.

Stephens: Hi. Can you give me a favor? Can you say Joy Lane?

Godwin: What?

Stephens: (repeats) Can you say Joy Lane?

Godwin: Joy Lane?

Stephens: Yeah, she's the reason this is about to happen to you. How old are you?

Godwin puts his arms up (he obviously sees the gun).

Godwin: Oh man, look, hey, listen, listen, I don't know, I don't know nobody by that name.

That's when Stephens shoots and kills Godwin, then continues to take video of Godwin lying dead on the sidewalk.

As Stephens walks back to his car, he says, That motherfucker dead because of you, Joy. Then he groans and says Murtis Taylor, Beech Brook, all that shit.