Democrats are accusing Florida House candidate Allen West (R) of being tied to the Outlaws, an infamous motorcycle gang.

West's campaign vigorously denies he's associated with the gang.

The evidence that's surfaced connecting West to the Outlaws isn't definitive, but it raises troubling questions for a candidate who is no stranger to controversy. West, a former lieutenant colonel in the Army, retired from the military after a 2003 incident in Iraq in which he fired two gunshots next to the head of an uncooperative, hooded detainee.

To connect West to the motorcycle gang, Democrats have pointed out he's a contributor to Wheels on the Road, a publication that covers the Outlaws' Florida clubs. And according to the publication's website, West was slated to appear at its anniversary celebration Saturday in Pompano Beach.

NBC News also obtained e-mails from West in which he said that references to the Outlaws shouldn't include the word "criminal."

"I was never more amazed at how members of the Outlaws guarded me during an interview," West said in an e-mail, according to NBC.

According to the Justice Department, the Outlaws are a violent criminal gang heavily involved in the drug trade. It's about the size of the Hell's Angels, according to a 2009 report.

West, who is challenging Rep. Ron Klein (D-Fla.), said he didn't defend the Outlaws in those e-mails. NBC's report also included photos of him at a recent rally that was organized by motorcycle clubs that say they're associated with the Outlaws.

Josh Grodin, a spokesman for West, vigorously denied West was associated with the Outlaws. "Allen is an African-American, this bike group doesn't accept black people," he said. "They have a history of racism against black people.

"I think it's a political hatchet job," Grodin added. "The Democrats are obviously desperate."

Grodin denied West was ever going to attend the Wheels on the Road anniversary rally. "It's never been on Allen's personal schedule to attend that," he said. West is instead set to attend a breast cancer charity motorcycle ride Saturday in St. Petersburg.

The controversy overshadowed West's impressive third-quarter fundraising haul. His campaign announced this week that he raised $1.6 million in the last three months. Klein, meanwhile, raised just $782,000.