Odds are, he decided that his friend was an infidel for smoking pot and killed him for it. Strange that the pot was dumped all over the body. Very strange. The guy was known to beat and berate his “wife” for not being muslim enough after her conversion. His brother-in-law said that he was not accepted by the two brothers because he was not muslim. I suppose that he was pretty conflicted if he knew that Dzhokhar was a pot head.
Maybe his friend was killed by someone at his mosque for “trying to drive huim away from ‘slam”.....
That seems to be what I think could be the cause, that or the bomber killed him for trying to de-radicalize him and he saw him as an “apostate”....