Possible Obama assassination attempt already?

Back in February I wrote of many progressives' fear for Obama. Tonight, on the first day of the convention, it appears that a substantial plot has unraveled. These guys may turn out to be simply racist addicts, but nobody worried much about the right wing militias before OK City. Here's hoping the Secret Service and FBI have already infiltrated the rest of the nuts.

The wire story:

(CBS4) ― CBS4 has now learned at least four people are under arrest in connection with a possible plot to kill Barack Obama at his Thursday night acceptance speech in Denver. All are being held on either drug or weapons charges. [...]

The story began emerging Sunday morning when Aurora police arrested 28-year-old Tharin Gartrell. He was driving a rented pickup truck in an erratic manner according to sources.

Sources told CBS4 police found two high-powered, scoped rifles in the car along with camouflage clothing, walkie-talkies, a bulletproof vest, a spotting scope, licenses in the names of other people and methamphetamine. One of the rifles is listed as stolen from Kansas.

Subsequently authorities went to the Cherry Creek Hotel to contact an associate of Gartrell's. But that man, who was wanted on numerous warrants, jumped out of a sixth floor hotel window. Law enforcement sources say the man broke an ankle in the fall and was captured moments later. Sources say he was wearing a ring with a swastika, and is thought to have ties to white supremacist organizations.

A third man -- an associate of Gartrell and the hotel jumper was also arrested. He told authorities that the two men "planned to kill Barack Obama at his acceptance speech."

That man, along with a woman, are also under arrest.

The Secret Service, FBI, ATF and the joint terrorism task force are all investigating the alleged plot.