The federal government is investigating Lance Armstrong for obstruction, witness tampering and intimidation, ABC News has reported.
A year ago in February, the U.S. attorney for Southern California dropped a two-year investigation of Armstrong.
The former seven-time Tour de France winner subsequently confessed in an interview with Oprah Winfrey last month to having used performance-enhancing drugs throughout his career.
Armstrong also faces a Wednesday deadline to cooperate with the U.S. Anti-Doping Agency in hopes of having his lifetime ban from competition reduced.
ABC News reported the current investigation is being conducted by an office other than the one that originally pursued Armstrong.
The previous investigation, anchored in Los Angeles where a grand jury was presented evidence by federal prosecutors and heard testimony from Armstrong's former teammates and associates, began with a separate investigation of Rock Racing, a cycling team owned by fashion entrepreneur Michael Ball. A reason for the termination of the investigation was not given at the time it was announced it would be ended.
Investigators had looked at whether a doping program was established for Armstrong's team while, at least part of the time, it received government sponsorship from the U.S. Postal Service. Authorities also examined whether Armstrong encouraged or facilitated doping on the team that helped him win the now-vacated Tour de France titles every year from 1999-2005.
The previous hurdle for prosecutors wasn't so much to prove whether any particular cyclist used drugs, but to determine if Armstrong and other team members violated federal conspiracy, fraud or racketeering charges. Unlike Barry Bonds and Roger Clemens, who testified before a federal grand jury and Congress, respectively, and were accused of lying under oath, Armstrong was never questioned in front of a grand jury.
Led by federal agent Jeff Novitzky, who also investigated Bonds and Clemens, U.S. authorities had sought assistance overseas, requesting urine samples of U.S. Postal riders from France's anti-doping agency and also meeting with officials from Belgium, Spain and Italy.
The investigation began after Novitzky was told about a cache of PEDs found by a landlord in the vacated apartment of Kyle Leogrande, a cyclist who rode for Rock Racing and had a doping ban, according to several people familiar with the case.
The case also was spurred by disgraced cyclist Floyd Landis. Another highlight came during a "60 Minutes" interview last May when former teammate Tyler Hamilton said he saw Armstrong use EPO during the 1999 Tour de France and in preparation for the 2000 and 2001 tours.
As the investigation progressed, Armstrong assembled a legal team, hired a spokesman and briefly created a website to address any of the allegations reported by the media.
Information from The Associated Press was used in this report.