...if that particular weapon, the one that was used in the crime, had a Mag capacity greater than 10 rounds, and was equipped with a flash hider, then yes, it was illegal.
Just wondering (quite honestly) - do you honestly think the murders would have been avoided by a non-flashed suppressed, 10 round cap rifle ? (two single shots got the dirty job done)
Would those "security features" have allowed the police to "intercept" the perp mid-crime ?
I'm seriously not trying to be patronizing... I'm trying to "get" your point of view...
BTW I just spent this weekend in San Fran... very nice city, albeit, completely overrun and dominated by hustlers and street people - even 60+ miles out of the city (aka Napa Valley) homeless people abounded.