I posted earlier that an article said their guns were legally obtained... that is what I read, but I'm not sure if that was accurate. 

Las Vegas law enforcement has not yet determined how Jerad and Amanda Miller acquired the firearms that they used in this weekend's attack that left two police officers, a civilian and the two attackers dead.
But in the weeks leading up to the attack, Jerad Miller posted multiple times on Facebook that he was looking for a gun and asked for help obtaining one.
"That would still be under investigation," Las Vegas Metro Police spokesman Larry Hadfield told TPM Tuesday when asked if authorities had determined how the Millers got ahold of the guns used in the shootings. He said investigators did not have any new information on what specific firearms were used.
http://talkingpointsmemo.com/muckraker/jerad-miller-guns-facebookBut in the weeks leading up to the attack, Jerad Miller posted multiple times on Facebook that he was looking for a gun and asked for help obtaining one.
"That would still be under investigation," Las Vegas Metro Police spokesman Larry Hadfield told TPM Tuesday when asked if authorities had determined how the Millers got ahold of the guns used in the shootings. He said investigators did not have any new information on what specific firearms were used.
Las Vegas police confirm Amanda purchased the revolver in Indiana. "She would have gone through the background check system. She didn't have any felony convictions or domestic violence charges, so forth and so on, or she wouldn't have passed. That doesn't mean she's smart or not insane," said Bob Irwin, owner of The Gun Store Las Vegas.
Police don't know who bought the other two weapons. As recently as May 8, Jerad was reaching out over Facebook for help obtaining a rifle. The same place he spewed his radical views about the oppressive American government and cop-hatred propaganda.
http://www.jrn.com/ktnv/news/Metro-police-tracing-guns-used-in-Sunday-killing-spree-262802271.htmlPolice don't know who bought the other two weapons. As recently as May 8, Jerad was reaching out over Facebook for help obtaining a rifle. The same place he spewed his radical views about the oppressive American government and cop-hatred propaganda.