GEOFF BENNETT: A new expose is revealing years of abuse and assault by a respected doctor at a top university medical center.

And the Ivy League school has admitted it failed too many women by waiting too long to stop him.

Amna recorded this conversation earlier.

AMNA NAWAZ: Columbia University has apologized to thousands of women for allowing an OB-GYN to continue practicing medicine unchecked after he sexually assaulted patients for over two decades.

The university has also created a $100 million settlement fund.

Dr. Robert Hadden was convicted in federal court last January and sentenced to 20 years in prison for enticing four patients to cross state lines, where he examined and assaulted them.

His conviction comes years after patients repeatedly warned the university medical center about his behavior.

Laura Beil is the co-author of ProPublica's investigation entitled "How Columbia Ignored Women, Undermined Prosecutors and Protected a Predator For More Than 20 Years" and host of the Wondery podcast "Exposed," which brought to light Hadden's assaults and the university's failure to act.

Laura, welcome.

Thanks for joining us.

LAURA BEIL, Host, "Exposed: Cover-Up at Columbia University": Thank you for the invitation.

AMNA NAWAZ: So, before we get into the university's role, help us understand the extent of Hadden's abuse between the early 1990s and his first arrest in 2012.

What were women saying happened, and how many women are we talking about?

LAURA BEIL: Well, to the last question, we actually don't know how many women we're talking about.

We know so far of more than 700 women who have come forward, but it could be in the thousands, given the length of time of his practice.

He came to Columbia in the late 1980s as a resident and started practicing in 1990 as a member of the faculty.

And from what we can tell, he started abusing women probably from the beginning.

The earliest patient that we talked to was a patient of his in 1992.

She was 16 years old at the time.

And so, during the course of two decades, he saw thousands and thousands of women.

And we really don't know yet the extent of his abuse, but we do know that it was pretty extensive.

AMNA NAWAZ: And what was the pattern of abuse?

What is it that women were saying happened?

They were being abused during their examinations with this doctor?

LAURA BEIL: Yes, they were being abused during the medical exams.

He did have certain patterns.

Sometimes -- a typical pattern is that he would wait for the public exam to be finished, and then the chaperone would leave, and he would find an excuse to reenter the room and saying, "Oh, I forgot something that I needed to do."

And when he was alone with them, he would abuse them.

But, that said, there were also women who said that they were abused while a chaperone was in the room.

So he pretty much took every opportunity to abuse women, but always during the guise of a medical exam.

AMNA NAWAZ: And some women did complain to Columbia's medical center.

What was the response for all those years?

LAURA BEIL: Yes, we documented women who tried to tell people at Columbia for years.

Sometimes, the women would have trouble articulating it, as you might imagine, given the breach of trust and the trauma.

And they would try to say: "Dr. Hadden made me uncomfortable.

Dr. Hadden, I find him creepy."

But there were instances where women were pretty explicit.

One woman in 1993 had one appointment with him just before her baby was born.

She sat down and wrote a multipage letter to the chairman of the department describing in detail what had happened to her.

So, it varied, but there were definitely warnings.

Columbia failed to act.

The warnings were dismissed.

The women were not believed.

If you're going to protect your patients from a predator like Robert Hadden, the first step is to actually believe that someone like Hadden can exist at your institution.

And so, on multiple occasions, the women's complaints were just dismissed or ignored.

AMNA NAWAZ: In 2012, there's a woman named Laurie Kanyok, who'd recently had a baby.

She went in for a follow-up, an exam with Hadden, and she was assaulted.

She reported it immediately.

That, in 2012, is what leads to Hadden's first arrest.

He gets a plea deal then, and he avoids jail time.

And you talked to Laurie as part of your podcast.

This is a clip from your podcast in which she's remembering when she learned that Hadden wouldn't go to jail.

LAURIE KANYOK, Patient: And she says: "You won.

He's taking a plea deal, and you stopped him."

And she goes: "The thing is, he's not going to have any jail time, but he is going to lose his medical license around the world.

And that's what you wanted to happen.

Am I right?"

And I was like, what -- why is that a win?

AMNA NAWAZ: Laura, what happens to Hadden after that arrest and plea deal?

LAURA BEIL: He went home.

He went home.

And that was just one of a series of betrayals that the survivors felt.

I mean, another huge one in Laurie's case was, after she called the police, after Hadden was arrested in his office the day of her assault, Columbia made the decision to let him go right back to work.

And he continued to see women for a number of weeks after his arrest.

AMNA NAWAZ: There is this turning point, when Evelyn Yang, who is actually the wife of former presidential candidate Andrew Yang, who was also assaulted, comes forward.

This is actually how she described her assault in a CNN interview.

EVELYN YANG, Patient: I was confused, and then I realized what was happening.

And then I just kind of froze, like a deer in headlights, just frozen.

I knew it was happening.

I remember trying to fix my eyes on a spot on the wall and just trying to avoid seeing his face as he was assaulting me.

I was just waiting for it to be over.

AMNA NAWAZ: Laura, why was that interview so important?

LAURA BEIL: And, at the time, her husband was running for president, and she realized that she had a platform to reach a lot of women.

And she made the very difficult decision to go public on CNN.

And that interview aired in January of 2020.

And immediately after that interview aired, women started coming forward in droves.

At the time of the interview, there were maybe about 30 women who had come forward.

A couple of months later, there were 90.

And so, when that happened, the scope, the true scope of Robert Hadden's abuse became clear.

And we're talking about someone who we now know was probably the most prolific sexual predator in New York history.

The scope became clear, and that caught the attention of the federal government.

The FBI started investigating him.

And then, in the fall of 2020, he was recharged with federal crimes.

AMNA NAWAZ: Laura, Columbia has announced the settlement fund, also an external investigation.

But how do the survivors that you talk to feel about those actions so far?

LAURA BEIL: The survivors I have talked to have mixed feelings about it.

On the one hand, they're happy that Columbia is finally taking steps to do the right thing, notifying women, an independent investigation.

These are things that they have called for, for a long time.

They are skeptical about the settlement fund, about the amount of it.

They have healthy skepticism, but they're also happy to see Columbia finally moving in the right direction and trying to do the right thing.

AMNA NAWAZ: That is Laura Beil, host of the Wondery podcast "Exposed."

Laura, thank you for your extraordinary reporting and for joining us today.

LAURA BEIL: Thank you.