Transcript for Theranos whistleblower: 'Your career will be ruined if this article comes out' Part 8
Reporter: "Wall Street journal" investigative reporter John carreyrou was about to blow the lid off theranos. Having gathered enough information from inside sources like Tyler Shultz, carreyrou was ready to publish. But he says he underestimated who he was up against. Good afternoon, my name is David boies. The outside counsel for theranos was David boies. It's a wonderful day for America. Reporter: David boies was known for being one of the most aggressive litigators of his time. One of Weinstein's lawyers, high powered attorney -- Reporter: He was on the winning side of history making cases. For theranos employees he was a scarecrow. They thought if they expressed their misgivings, that it would be David boies and his law firm that would be coming after them. They get him to take on "The Wall Street journal" and any other news outlets that even came into the crosshairs of theranos. David boies and two of his associates at boies Schiller came to our newsroom. Their demeanor was very aggressive. They had proceeded to tell us that I had misappropriated theranos trade secrets. A 23-page long letter comes a few days after that and that letter is essentially a searing indictment of me as a journalist and the and the threat is very explicit that theranos is going to sue if we proceed any further with this story. Reporter: But it wasn't just the journal that theranos was threatening. Did theranos have a private investigator follow at any time to your knowledge? Yes. Tyler emails me to let me know that theranos lawyers knew that he and I had met. My dad asked me have you been speaking with a "Wall Street journal" reporter. I said yes. He said they know. You are totally . Unhow aggressive they are. So then I called my grandfather. And he said, "There is a one page confidentiality agreement, and if you sign it, they will make everything go away." And I said, "That sounds fine, but can I come talk to you in person first, without any lawyers around?" And he said, "Yes." Tyler shows up at his grandfather's place and he thinks he is going to talk just to his grandfather. I reiterated my concerns. And he continued to believe in what Elizabeth had told him. And then, he just says, whatever the case may be, will you just sign this one page document to make everything go away? I said yeah, I will definitely sign that. He said there are two theranos lawyers here right now. Can I go get them? There just happened to be two lawyers hidden somewhere in the house? Yeah. And what was your reaction to learning that? Yeah, I was totally surprised. Those two attorneys proceed to come down and are extremely aggressive with Tyler. They tried to get him to sign a document naming "The journal's" other sources. Did you ever sign anything? Never signed anything. Tyler withstands this unbelievable pressure. My grandfather would say things like your career will be ruined if this article comes out. Over the course of the next several months, his attorneys negotiate with theranos attorneys. Ends up costing his parents close to a half million dollars in legal fees. But, stays firm and in the end I am able to publish. Reporter: On October 15th 2015, "The Wall Street journal" ran the first of many bombshell reports that stated, among other claims, that the company wasn't "Using its technology for all the tests it offers" but instead, was using "Traditional machines bought from companies like Siemens" to run the majority of its tests. At first, people kind of didn't know what to make of it. There's ten years of articles saying that this is the greatest company that ever set forth in silicon valley and this is the greatest CEO they've ever had. And then there's this wall Street journal article saying, "No, none of that is correct." I found myself thinking ah, man. I hope that reporter's wrong. I wanted to believe so badly how great it would be if this were true. But it turned out not to be. And so, instead, you start thinking, god, does she really believe this stuff? Elizabeth, I have to tell you in all my years I can't recall a private company that I think candidly many have never heard of getting this kind of attention and scrutiny. What do you think is going on here? This is what happens when you work to change things and first they think you're crazy. Then they fight you. Then all of a sudden you change the world. Oh, come on. No. No, enough. Enough Elizabeth Holmes. Enough with this belief in yourself. I have to say, I personally was shocked to see that "The journal" would publish something like this. Enough with this insanity in the face of an article that basically says listen this company is a fraud. Reporter: But Elizabeth's next fight wouldn't just be in the court of public opinion. Do you swear to tell the truth, the whole truth, and
This transcript has been automatically generated and may not be 100% accurate.