PORTLAND, Ore. — A young couple accused of killing four people in a multistate crime spree last fall have been indicted of federal racketeering charges alleging the rampage was part of a campaign to ‘‘purify’’ and ‘‘preserve’’ the white race, Amanda Marshall, the US attorney for Oregon, said Friday.

A federal grand jury handed up the indictment Thursday against David ‘‘Joey’’ Pedersen, 32, and Holly Ann Grigsby, 25, Marshall said in a news release.

Grigsby will be arraigned Monday in Seattle. Pedersen will be arraigned in Portland, but that has not been scheduled.

‘‘The indictment in this case alleges horrendous crimes were committed as part of defendants’ white-supremacist campaign to kidnap and murder targets on the basis of race, color, religion, and perceived ‘degenerate’ conduct,’’ Marshall said.

They are charged in the killing, kidnapping, and robbery of four people last fall: Pedersen’s father, David ‘‘Red’’ Pedersen, and stepmother, Leslie ‘‘DeeDee’’ Pedersen, on Sept. 26 in Everett, Wash.; Cody Myers, a 19-year-old from Oregon, on Oct. 1; and Reginald Clark, 53 of Eureka, Calif., on Oct. 3.

The 24-page indictment alleges that Pedersen and Grigsby robbed their victims to finance their white supremacist movement, stole their cars to escape, and murdered them to eliminate witnesses.

The indictment also states that Pedersen had researched the names and addresses of Jewish organizations in Seattle, Portland, and Sacramento, Calif., to identify potential targets for elimination. ‘‘He possessed a draft ‘press release’ to alert the media about the purpose of the planned murders,’’ the indictment states.