Las Vegas - Las Vegas police said on Monday that the two suspects in the shooting deaths of two officers had ideology that was along the lines of "militia and white supremacists".
Police are also looking into whether Jerad Miller and his wife, Amanda had been at Cliven Bundy's Nevada ranch during a stand-off with government agents earlier this year.
Bundy, who rejects the authority of the federal government, got into a high-profile showdown with US officials who say he owes more than $1m in fees and penalties for grazing his cattle on government land. Hundreds of supporters, some of them armed, went to the ranch to support Bundy.
Assistant Sheriff Kevin McMahill said the two suspects believed that law enforcement was the "oppressor".
McMahill said the shootings were an isolated act and officers were still looking for a motive.
The two officers were having lunch at a strip mall pizza buffet when the Millers fatally shot them at point-blank range in an ambush. The suspects then fled to a nearby Wal-Mart, where they killed a third person and then themselves in an apparent suicide pact, authorities said.
The attack at a CiCi's Pizza restaurant killed Officers Alyn Beck, 41, and Igor Soldo, 31, who are both husbands and fathers. Jerad Miller yelled, "This is a revolution!" McMahill said.
McMahill said at a news conference on Monday that both suspects fired multiple shots into Beck. They then placed a note, a yellow "Don't tread on me" flag and a swastika on the officers' bodies.
The deadly rampage in the ageing shopping centre about 8km northeast of the Las Vegas Strip took place in a matter of minutes.
Police were called at 11:22 to the pizzeria. Shots were reported five minutes later at a nearby Wal-Mart, where the shooters gunned down 31-year-old Joseph Wilcox of Las Vegas just inside the front door and exchanged gunfire with police before killing themselves, authorities and the Clark County coroner's office said.