I doubt most homeless men wear suits.
His pant leg and some of the sleeve of the suit were mentioned as dirty by people who saw him and as I saw in the video. It looks to me like he had been on the ground at some point. I don’t think the shoe tells us anything really.
This is a different video than what I saw earlier. No time stamp, but more movements.
http://online.wsj.com/video/surveillance-footage-of-john-wheeler-released/6B7EC361-7201-41A3-B385-6F1834B89793.html
If he'd fallen down in snow. It would have melted not leaving any dirt but a wet spot or be white.
If he had fallen on dry dirt is would have just brushed off, like the ashes from my wood stove.
It had been snowing and was still very cold during that week. The ground was frozen. Falling on it would be like falling on rocks. It would not adhere to his clothes.
What appears on his clothes is mud. He was knocked down in the mud....
Where was there mud?