Washington, Aug.28 : The three white supremacists with a sniper rifle and high on drugs who were arrested near the Democratic convention in Denver will not face charges even though officials believe that they wanted to assassinate Barack Obama.
The FBI and the US Secret Service carried out an "intensive" investigation into the plot - in which the supremacists talked of shooting Obama as he accepted the Democratic presidential nomination in an open-air sports stadium on Thursday night - but found insufficient evidence of a "true threat".
One of the suspects, Shawn Adolph, 33, was connected to a high-velocity Ruger sniper rifle seized during a series of early morning arrests on Monday and had made clear threats and "racial slurs" against Obama, Troy Eid, Denver's US district attorney said.
The specter of assassination arose in May when Hillary Clinton had to apologize after appearing to suggest that the assassination of Robert Kennedy in 1968 during his presidential campaign was a good reason for her staying in the race.
Obama is often compared to John F. Kennedy. But it is his skin colour that has added to concerns in a country that has more than 200 million legally held firearms and 30,000 gun deaths each year.
Eid said: "It is a serious federal crime to make a threat against a presidential candidate."
The three men, Adolph, his cousin Tharin Gartrell, 28, and Nathan Johnson, 32, have long criminal records for illegal gun possession, drug dealing and theft. There were multiple outstanding warrants for their arrest and all three were being held on drug and firearms charges last night.
Obama, who was given Secret Service protection earlier than any other presidential candidate, has played down fears about his safety.
Yet a poll released in Michigan found that 57 per cent of respondents agreed "there are people who want to hurt Barack Obama because of his race".
He travels with a retinue of six Secret Service agents at all times. Security in Denver is intense, with nearly 1,500 police officers from across Colorado brought into supplement those from the city, as well as the Secret Service, the US Capitol Police and the National Guard.