DENVER -- A federal prosecutor in Denver said he doesn't know if security plans will change at the Democratic National Convention following alleged racist threats against Barack Obama.

U.S. Attorney Troy Eid said the three suspects were high on drugs when the alleged threats were apparently made. He said the men were not serious about carrying out the threats.

"Please understand that the law recognizes a difference between what we call a true threat -- that's one that can actually be carried out -- and the reported racist rantings of drug abusers," Eid said. "The jargon for this sometimes is, 'It was more aspirational than operational.' In this particular case, there's insufficient evidence that there was any kind of plot or conspiracy."

The statements are still being investigated, but the federal arrest affidavit said that their only motivation to kill Obama was his race. In the federal arrest affidavit, an agent with the Alcohol, Tobacco and Firearms Bureau wrote that Johnson told a Secret Service agent, described only as SA Torres, that "Adolf had, in fact, threatened to kill Obama on a prior occasion ... that he wanted to kill Obama on the day of his inauguration and ... would specifically use a 22-250 sniper rifle." Special Agent Shane Abraham of the ATF went on to write, "Johnson then told (SA Torres) there were no political reasons for wanting to kill Obama, the only reason is because Obama is black."

Authorities said the suspected drug users were arrested near Denver this weekend with methamphetamine, guns and bulletproof vests.

They are charged with drug and weapons offenses but not with threatening to assassinate Obama or with other national-security-related crimes.