Centennial -- Fliers promoting "white history month" were posted on doors and porches in two subdivisions - the latest example of a leaflet attributed to a white supremacy group.
An unidentified resident reported the incident to the Arapahoe County Sheriff's Office on Sunday evening.
"It's always of note when we have people distributing this kind of stuff," Capt. Phil Spence said.
Fliers were distributed in the 7600 to 7900 blocks of South Harrison Circle and in the 7900 to 8200 blocks of S. Marion Circle.
The fliers, headlined "Leif Eriksson discovers America, 1000 AD" declares October "white history month" and urges people to join a group, with the slogan "We're looking for a few good Vikings."
Last month, anti-Semitic fliers were posted on bulletin boards at the Norlin Library and Duane Physics building of the University of Colorado-Boulder.
The fliers contained a reference to the National Alliance , which is based in West Virginia.
Bruce DeBoskey, regional director for the Anti-Defamation League, which monitors hate groups, said he isn't surprised at the latest incident.
"This is a period of lot of activity from the National Alliance," he said Monday.
Spence recounted similar incidents in Arapahoe County this year. Other fliers decried immigration policy and mixing of races, he said.
"The recurring theme is keeping America white," Spence said. "I guess they forgot the American Indians were here first."
Spence noted that while people may object to the fliers, they are protected by the First Amendment, which means law enforcement must walk a fine line.
"We don't always agree with what is published, whether it's positive or negative, but our role is to keep the peace," he said.
"We don't get involved unless there's specific threats or acts of violence."