I think most people here failed to understand between what killed young Grunwald....and what motivated the killing. Motive for murder, I think, is what James Mason may be saying in his rather clumsy way. What was the motive for murder.....it was that the killer believes that Grunwald smoked all the pot and he felt what...robbed...disrespected.....angered or all three. Such motivation caused the murder. It really doesn't matter if it true or not. You are looking at from a mind of 16 years old sociopath. To him, the pot was the cause and effect of this terrible crime. Does this make sense to anyone?? (Most people don't think about motive as they think about the tools of murder. That is why the liberals blame the gun for all evils. Motive is what the perpetrator act upon and in this case, it was over pot or loss of that pot slash. I don't know why people are getting hysterical over the pot thing. It could happen over jacket, pair of sneakers or whatever.)