Transcript for Lance Armstrong Agrees to Testify
Now, to the big headline overnight on lance armstrong. Just hours before the deadline that would have meant he was banned from cycling for life, abc news learned that armstrong would, in fact, cooperate with the anti-doping investigation. And that time shortly after abc's neal karlinsky broke the news of a federal investigation into armstrong. And neal joins us now with the very latest on all of this. Good morning, neal. Lance armstrong is not a man who scares easily. But sources say one thing he does fear is jail. And that may have been the motivator to finally get him in the door to speak with authorities. It is a stunning about-face. At the very last minute, just before his deadline to talk to u.S. Anti-doping authorities, lance armstrong is giving in and apparently will come clean. In a statement, usada's ceo writes that armstrong wants to be part of the solution and assist in the effort to clean up the sport of cycling. The turn came just hours after abc news broke the story that federal agents are reportedly investigating armstrong for witness tampering, obstruction, and intimidation, serious federal crimes. Allegations that armstrong threatened witnesses that planned to expose his big lie. The reality is that lance armstrong did not want to be a participant in any dealmaking. And he got scared. Reporter: Coming clean to orities isn't lialking to oprah. Did you ever take banned substances to enhance your cycling performance? Yes. Reporter: Armstrong will have to do what he's fought hard to avoid. Testifying under oath with perjury charges at stake. The testimony could take days and will require armstrong to provide substantial assistance to investigators. Meaning, he must name names, who helped him get the drugs. Who helped him hide and transport them. Pass the drug tests and keep the secret hidden for so long. He'll essentially have to roll over on people he seemed interested in protecting. Planet armstrong is a dark and lonely place right now. He's got major problems. Reporter: A pile of civil lawsuits are active, as well. Including a class-action suit by people who bought armstrong's best-selling books. Defendants knew or should have known these were fiction. U.S. Doping authorities have given armstrong a two-week window to come in and talk to them. We'll see. On the possible upside for armstrong, in hopes that cooperating with authorities now will somehow give him a break and help out with some of his other, many, legal problems.
This transcript has been automatically generated and may not be 100% accurate.