High-powered assault rifles aren't that hard to find — even for a convicted felon like Lovelle Mixon. The kind of AK-47 that Mixon used to kill Oakland police officers Saturday can be had on the street for as little as $400. Often they come from Nevada, where selling assault rifles is perfectly legal, unlike in California. Then they are brought to the Bay Area and resold. If the buyer has a criminal past, "they have a friend — usually a girlfriend with no record... (GunPolicy.org)