If you were on the jury in this case, how would you vote on Steve Harmon? Discuss your reasons for coming to this decision.

This is a great question because it is very open ended. As a classroom debate topic, I have students that fall into both guilty and not guilty camps. It is entirely up to you to defend what you think.
I realize that the concept of "innocent until proven guilty" is the place that all jurors are supposed to start, but I believe that's also unrealistic. Steve is on trial. He was caught by law enforcement officers, so there has to be some question as to validity of Steve actually being innocent. His "friends" don't really help out a juror's suspicions. King, Cruz, and Alou are all known thugs in a rough neighborhood, and we find out in chapter 14 that King invited Steve to the drugstore "payday." We also know from chapter 7 that Steve thinks those tough guys in his neighborhood are pretty cool.

I had looked at him and wanted to be tough like him.

Finally, Steve admits that he was at the drugstore looking for some mints. None of this evidence is definitive proof that Steve is guilty of anything, but it doesn't prove his innocence either.
On the other hand, his innocence seems to fit more in line with Steve's personality. He may look up to the thugs in the neighborhood, but when it comes down to it, Steve is quite scared of jail and violence. He's a good kid, and Mr. Sawicki states the same thing. Steve might run with a rough crowd every now and again as a result of where he lives, but Steve is not guilty of being part of a murder.