LOS ANGELES, Calif. and#8212; An attorney representing Tyler Hamilton said Tuesday he felt compelled to notify federal authorities about a brief conversation involving his client and fellow cyclist Lance Armstrong that occurred over the weekend at a Colorado restaurant.

Hamilton, who has accused the seven-time Tour de France winner of doping, and Armstrong ran into each other in Aspen on Saturday night. Attorney Chris Manderson said his client was rattled by some of the comments made by Armstrong and he told federal authorities on Monday about what occurred.

“It was aggressive and intimidating and we thought it should be reported to federal investigators,” Manderson told The Associated Press.

Federal officials are now in their second year of investigating doping in cycling. A Los Angeles-based grand jury is hearing evidence that could lead to charges of fraud, conspiracy and drug trafficking against Armstrong and his former teammates.

Thom Mrozek, a spokesman for the U.S. attorney’s office, declined comment.

Manderson added it was well known that Hamilton would be in Aspen; he believes Armstrong sought his fellow cyclist out for a confrontation.

“I don’t think it was a coincidence,” he said.

Armstrong told Outside Magazine the incident was “certainly awkward for both of us” and “truly uneventful.”

Armstrong attorney Mark Fabiani said the meeting was a nonevent, and offered up a list of witnesses to back up his claim.

Manderson said the two men haven’t spoken to one another in years and hadn’t in recent weeks after Hamilton, a former Armstrong teammate, appeared on “60 Minutes” where he made doping allegations against the champion cyclist.

The Hamilton interview reasserted claims made a year earlier by Floyd Landis, another former teammate of Armstrong’s.

Manderson declined to say whether Hamilton would appear before the grand jury again, but hopes federal authorities will interview some of the people in the bar who witnessed what occurred, including those in Armstrong’s entourage.

“I hope federal investigators interview the restaurant owner and those in Armstrong’s entourage under penalty of perjury to force them to tell the truth about the incident,” Manderson said.