In the third mass shooting in three weeks in the western US, the couple shot the police in cold blood at a Las Vegas pizza restaurant, before killing a civilian at a nearby Walmart and then committing suicide.
Jerad and Amanda Miller saw police as Nazi-style oppressors, and claimed links to a Nevada cattle rancher who won a high-profile standoff with authorities two months ago with the help of pro-gun militias.
"This is the beginning of the revolution," read a note pinned on one of the bodies by Jerad Miller, 31, after he and his 22-year-old wife slaughtered the cops on Sunday, said assistant sheriff Kevin McMahill.
"There's no doubt that the suspects have some apparent ideology that's along the lines of militia and white supremacists," he said, the morning after the massacre which left five dead.
The couple entered the restaurant, walked past the booth where the officers were eating, and then Jerad Miller "pulled a handgun out and shot officer (Igor) Soldo one time in the back of his head," said McMahill.
"Officer Soldo immediately succumbed to his injuries. At that time, officer (Alyn) Beck immediately began to react, when he was confronted by lethal gunfire from Jerad Miller, and he was shot once in the throat area," he told reporters.
The couple then both shot multiple rounds into the two officers, before pulling the bodies out of the restaurant booth.
- 'Swastika on top of body' -
They placed an American revolutionary flag on one of the bodies, "and also threw a swastika on top of his body." Jerad Miller then "pinned a note to officer Soldo basically stating that this is the beginning of the revolution."
Officers were still investigating the motive for the attack.
While suggesting some kind of militia link, McMahill said: "We believe at this point, with the swastika, we don't necessarily believe that they are white supremacists or associated with the Nazi movement.
The couple eventually holed up in the back of the Walmart store, where Amanda Miller shot her husband before taking her own life.
Police were investigating links to Cliven Bundy, a Nevada cattle rancher who billed himself as a people's hero, who was locked in a showdown with US federal authorities earlier this year.
Bundy also became the unlikely ring-leader of a spontaneous armed right-wing militia, who sprang to his defence to prevent federal police from removing his cattle.
Jerad Miller said on his Facebook page that he was at the Bundy ranch, further north in Nevada, during the cattle standoff. CNN reported Miller was seen in video of the Bundy standoff in April.
The Millers only moved to Nevada from Indiana in January. Jerad Miller had a criminal record in Washington state and wrote on Facebook he was kicked out of the Bundy ranch because of his criminal background, said McMahill.
The Vegas shooting is the latest in only a few weeks in the former Wild West region of the United States.
On May 23, a student with mental problems, the son of a Hollywood director, went on a gun rampage at a college campus in Santa Barbara, north of Los Angeles, killing six people and then himself.
On June 5, a gunman killed one person and injured two others on on a college campus in the northwestern US city of Seattle, in what the local mayor denounced as America's "epidemic of gun violence."
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