Note the fanny pack and hat he’s wearing that isn’t seen at the end. It wouldn’t surprise me if one of those is what’s on the ground in front of Slager later.
The family says he’d bought it, so it could just be tragic coincidence that he just happened to give the kind of responses thieves give when nabbed. It’s always “my friend’s car”, or my (choose relative)’s car”, or “I just bought it, but we haven’t done the paperwork yet”. That would have made Slager suspicious, and the guy running off is just the kind of thing that would have convinced him he was chasing a fleeing felon.
He had a bench warrant for failure to pay child support ($18,000, which is a fair chunk of change). I don’t know why he thought he could get away by running, but people do stupid things.
But RUNNING AWAY does not justify shooting him. They knew who he was and could pick him up later easily enough, and he was not wanted for a major violent felony in the first place.
The buddy in the passenger seat should be able to enlighten us all on why he ran.