US federal agents are investigating disgraced former Tour de France champion Lance Armstrong for crimes including obstruction, witness tampering and intimidation, reports said Wednesday.
Citing an unnamed source, ABC News said the current probe is focused on different charges from those previously investigated.
US Attorney Andre Birotte, who led the federal probe that was dropped last year, said he had no plans to press charges despite Armstrong's recent doping admissions, but he did not definitively rule out such action.
Sarah Clark-Lynn, a spokeswoman for the US Food and Drug Administration (FDA), told USA Today that the organization, which deals with food and drug safety, is investigating Armstrong, but would not say on what grounds.
"When the US Attorney's Office declines to prosecute an individual or entity, typically law enforcement agencies do not pursue further investigative activities," she said.
"That said, this is an ongoing matter for the agency and I cannot comment further."
FDA agents were prime among those who gathered evidence in the prior case against Armstrong.
Birotte's investigation was centered on doping, fraud and conspiracy and Armstrong's denials of such crimes when he was the lead rider in the extremely successful government-funded US Postal Service Team.
"Obviously we've been well aware of the statements that have been made by Mr Armstrong and other media reports," Birotte said, referring to Armstrong's bombshell doping confession to chat show legend Oprah Winfrey last month.
"That has not changed my view at this time. Obviously we'll consider -- we'll continue to look at the situation," Birotte told reporters in Washington.
The ABC News source, quoted on condition of anonymity, said: "Birotte does not speak for the federal government as a whole. Agents are actively investigating Armstrong for obstruction, witness tampering and intimidation."
For years Armstrong denied doping, but he was banned last year after the US Anti-Doping Agency (USADA) gathered compelling testimony that he had been the ring-leader of a large-scale and highly-organized doping conspiracy.
Former Armstrong teammate Tyler Hamilton opened the door to possible witness tampering issues in an interview with CBS News broadcast last month as part of a "60 Minutes" story with USADA chief Travis T. Tygart.
Hamilton told CBS that he was confronted by Armstrong in 2011 only three weeks after a prior interview with "60 Minutes" aired in which Hamilton made revelations about Armstrong.
Hamilton told CBS he was in a crowded bar in Aspen, Colorado when Armstrong approached him.
"Turned to my right and it was Lance Armstrong," Hamilton said. "Stops me cold. First he asked how much '60 Minutes' had paid me to do that interview. Obviously, nothing.
"The biggest thing he said is, 'You know, we're going to make your life a living, f-ing hell, both in the courtroom and out.'"
Hamilton said he felt intimidated by Armstrong and, at that moment, Hamilton was a witness against Armstrong in what was an active federal investigation.
Armstrong was given a Wednesday deadline to come clean under oath about his doping activities, and others who were involved in the cheating conspiracy, in order to have any hope of USADA reducing his lifetime ban from competition.
Armstrong attorney Tim Herman told USA Today that Armstrong would not meet that deadline, saying his client wants to testify to the International Cycling Union (UCI).
USADA's evidence showed UCI officials might have turned a blind eye to enable Armstrong's doping scheme.
Armstrong faces other legal battles after being stripped last year of his record seven Tour de France titles.
Dallas insurance company SCA Promotions has already demanded the return of $12 million in bonuses it paid to the disgraced Texas rider for achieving five consecutive Tour victories.
SCA attorney Jeff Dorough told AFP that the firm expected to file a lawsuit against the 41-year-old as early as Wednesday.
"Both he and his lawyers almost taunted us and said, 'If we are ever stripped of those titles, we will give you the money back,'" SCA attorney Jeffrey Tillotson told CNN on Wednesday.
"I think, at that time, Mr Armstrong thought he would never be caught. Of course, he has been caught, exposed, confessed, admitted essentially to perjury. We ask him to finally live up to his word and give that money back."
Herman said Armstrong doesn't plan to repay the money.