GEOFF BENNETT: A new U.N. investigation finds conditions inside the American prison at Guantanamo Bay, Cuba, are cruel, inhuman and degrading more than 20 years after the U.S. started sending detainees in the so-called war on terror to what's called Camp Justice.

Roughly 780 detainees have been held at the detention center since it opened in early 2002.

Today, 30 people remain, 16 of whom have been cleared for release.

The report was the result of the first ever visit to Guantanamo Bay by an independent U.N. investigator.

Its author, Fionnuala Ni Aolain, is the U.N. special rapporteur on human rights and counterterrorism and a professor of law.

And she joins us now.

Thank you for being with us.

FIONNUALA NI AOLAIN, U.N. Special Rapporteur on Human Rights and Counterterrorism: Glad to be here.

GEOFF BENNETT: You're the first United Nations investigator to be granted access to the detention center in its more-than-two-decade history.

You spent four days there.

As we mentioned, in your report, you say the government's treatment of detainees is cruel, inhuman and degrading.

What exactly did you see?

FIONNUALA NI AOLAIN: So, I was indeed the first a U.N. expert to go to the detention facility.

Few states have the courage to let an investigator like myself in and to expose all of the treatment and to allow an assessment of that kind of facility.

And so I'm grateful for that.

But the report is also critical.

It recognizes that there are enormous deficits which remain in health care, in the standard operating procedures, in shackling, in even the naming of these men.

They're called by numbers, not by name.

All of these things led to a cumulative finding of cruel, inhuman and degrading treatment under international law.

GEOFF BENNETT: The U.S. government says it disagrees with many of your findings and assertions.

Part of a statement from the Biden administration reads this way: "We are committed to providing safe and humane treatment for detainees at Guantanamo, in full accordance with international and U.S. domestic law.

Detainees live communally and prepare meals together, receive specialized medical and psychiatric care, are given full access to legal counsel, and communicate regularly with family members."

Does this statement square with what you witnessed and with what the detainees told you?

FIONNUALA NI AOLAIN: Yes, so I have to say, of course, there have been improvements.

And I recognize that minimum standards are met.

But this is an aging, vulnerable population, all of whom are survivors of torture.

The standard operating procedures are pervaded by arbitrariness.

And that was told to me not just by the men that I spoke with, their lawyers, but also even the guard force itself.

Men are shackled as they move within the facility.

They were shackled when they met me.

Again, under international law, we only use those kinds of restraints as a measure of last resort, when there's an urgent or compelling need to use them.

And, as you have just said, 16 of these men are cleared for transfer.

They pose no security problem because they are being ready for transfer.

And, of course, the hardest thing was to hear the real, deep, profound psychological trauma that these men live with.

And as I spoke to them, what I learned was of enormous anxiety and pain.

For so many of these men, the dividing line between the torture of the past and the conditions of the present is whisper.

It's so thin.

And, for some of them, it doesn't exist at all, because there's been no comprehensive torture rehabilitation.

GEOFF BENNETT: You have said the U.S. government should apologize for the cruel treatment at Guantanamo Bay.

You have also said the harsh treatment is a betrayal of the rights of victims of the 9/11 attacks.

How do you justify those comments, saying the U.S. should apologize to the detainees responsible for the deadliest attack in U.S. history, and then drawing a connection between their treatment and the rights of people who fell victim to their heinous acts of terrorism?

FIONNUALA NI AOLAIN: I encourage people to read my report, because, actually, what this report does is, it provides a clear road map for the U.S. government to actually fully provide for the rights of victims of terrorism, including a comprehensive audit for the 9/11 families of all their psychological and medical support.

It's deeply concerning to me that many of those families don't have the security of long-term psychological treatment.

But I also say clearly in this report that the single largest barrier to the rights of victims of terrorism, which I absolutely defend, to have accountability for acts of terrorism, was torture.

Those who tortured betrayed the rights of victims, because what they ensured is that you couldn't have fair trial.

What they ensured was that the trial process would be so hampered, as we have seen for the last decade, that it would be impossible for the victims of terrorism to redeem their rights.

So, in fact, victims of terrorism are due an apology for torture, because it was the very torture that was done, sometimes in their name, that has prevented them from actually ensuring the fulfillment of their rights.

I would say, as to the men, let me be clear.

Torture is the most egregious and heinous of crimes.

Even in situations of war, we don't accept that people can torture.

We say this to Russia.

We say it to China.

We say it to many, many countries across the globe.

Whether you're a P5 member or just a small state, you are not allowed to torture.

And when you do torture, you bear the responsibility of that, which includes apology to the people that you have tortured.

GEOFF BENNETT: President Biden has said that he wants to close Guantanamo Bay by the end of his term.

What obstacles remain, as you see it?

FIONNUALA NI AOLAIN: Well, I think many of U.S. are committed to closure.

The U.N. has called for closure.

The president has rightly called and committed for closure.

But the path to closure is not simple.

And my report also recognizes those challenges.

One of the things that I make clear is that closure has to be human rights-compliant.

And as the government takes forward its closure path, it has to do so in a way that's compliant with international law.

I think one of the things I would say is that, given that closure is not likely immediate, there are some options for the U.S. government.

One is to transfer individuals to military bases overseas, in compliance with their legal and constitutional obligations.

The second is to transfer them to governments.

But, if they do that, they have to make sure that they're treated fairly and with dignity, and not retraumatized.

And maybe the final, most important thing that this government can and will do, I hope, is to de-exceptionalize Guantanamo.

Treat these elderly, disabled, harmed men as victims, as much as anything else.

Sixteen of them are cleared of any crime, of any responsibility.

Those men should be released and repatriated as soon as practicable.

GEOFF BENNETT: Fionnuala Ni Aolain is the special rapporteur on human rights and counterterrorism for the United Nations.

Thank you for being with us.

FIONNUALA NI AOLAIN: Thank you.