Ask Stan what he thinks about arson. He claims he doesn't like it.

Ask him if he visited Gray. He says he might have walked by.

A bit more pressure and Stan leaps up and confesses to torching the house because Gray picked on his friends. Isn't that special! Case closed.

I got 99% of the evidence with 0 hints for 99% complete. I'm an "Investigator". 6/10 extras are sketches of the scenes.

CSI Crime scene Investigation Walkthrough