Bodycam footaged released

http://abc7news.com/bodycam-footage-released-in-north-beach-officer-involved-shooting/3604433/

Summary:

A policeman stopped a group of guys and one of the men ran and tossed his gun the officer then shot him in the back twice. The reason i chose this article is because I just previously watched it on the news. The news woman talked about his past charges and what he is convicted of. I do not understand why they decided to tell about the person’s past to make them seem like a bad person. Their past has nothing to do with what happened and why he was shot. My question is why do they find it significant to add their past to make them look bad? Why not tell the officer past as well in that case?