JOHN YANG: Good evening.

I'm John Yang.

What comes next in Syria, now that the Assad regime is history, was the topic at a meeting in Jordan today of top officials from the region, from the European Union and from the United States.

Secretary of State Antony Blinken outlined some of the principles they discussed.

ANTONOY BLINKEN, U.S. Secretary of State: The rights of all Syrians, including minorities and women, should be respected.

Humanitarian aid should be able to reach people who need it.

State institutions should deliver essential services to the Syrian people.

Syria should not be used as a base for terrorist groups or others who threatened Syria's people, its neighbors or the world.

JOHN YANG: Under the Assad regime, hundreds of thousands of Syrians were swept up by the security apparatus, never to be seen again.

Simona Foltyn gained access to one of the intelligence branches that orchestrated that brutal repression.

She tells us what she found.

SIMONA FOLTYN (voice-over): The search for the disappeared continues in Damascus.

At the Palestine branch of Assad's feared intelligence services, relatives pour over stacks of notebooks, sift through piles of passports taken from prisoners in hope of finding a trace of their loved ones.

Ibrahim and Hussain are each looking for their brothers who've been missing for years.

They don't know for sure if they passed through this particular prison.

They're flipping through a registry where guards recorded every new arrival.

IBRAHIM MOHOAMMED, Brother of Disappeared Person (through translator): Everyone who entered.

Their name is here, the date is here, what they confiscated, which day, what time.

SIMONA FOLTYN (voice-over): The Palestine branch was one of several security agencies that enforced Assad's tyrannical rule.

Each had its own prison where people were disappeared, tortured and killed.

HUSSAIN HAMOUD, Brother of Disappeared Person (through translator): The way it happened, they rotated them through four to five different branches, and each branch did their own investigation as they pleased.

SIMONA FOLTYN (voice-over): This is the second prison facility Ibrahim and Hussain have been to.

With each day, the hope of finding their brothers alive fades away.

HUSSAIN HAMOUD (through translator): God is generous.

We don't know if we'll find them, but God is generous.

They say that the cars took away the prisoners.

Where?

We don't know where.

They took them away Wednesday, Thursday and Friday, just before the liberation.

SIMONA FOLTYN (voice-over): Knowing the truth, at least, would provide some closure.

The one thing they do know is that justice must be served.

HUSSAIN HAMOUD (through translator): The person who used to run this branch, where is he today?

Where did he go?

He's here.

In this country, no matter who he was, the responsible authorities have to be brought to account for what they did to the people.

IBRAHIM MOHOAMMED (through translator): Every judge, officer, deputy officer, guard, anyone responsible must be brought to account.

HUSSAIN HAMOUD (through translator): Everyone who was loyal to them is one of them, whether he was the guard at the door or the head of the prison.

SIMONA FOLTYN (voice-over): Assad's government kept meticulous records of its own crimes.

That includes the names of his henchmen.

The rebel's offensive took them by surprise, and there was no time to destroy incriminating evidence.

In the main building, we found a register of rotations officers who worked at this branch.

SIMONA FOLTYN: What this book contains are the names of all the officers who worked here who might be responsible for some of the crimes that have been committed here.

So this is a really crucial piece of evidence.

The problem is there doesn't appear to be a process to safeguard these documents which will inevitably be really important for any future justice and accountability process.

SIMONA FOLTYN (voice-over): The rebels are now guarding the compound.

Ahmed Al Shibli was imprisoned for months inside Palestine Branch before joining the armed opposition.

This was the first time he returned.

AHMED AL-SHIBLI, Former Detainee (through translator): The cells are underground.

We can go down there.

I am shaking every time I remember this place.

SIMONA FOLTYN (voice-over): We proceed downstairs into the darkness where the prisoners were held.

AHMED AL-SHIBLI (through translator): There would be 50, 60 people here in this cell.

When they entered the cell, I'll show you how it was whenever they opened this window.

SIMONA FOLTYN (voice-over): Ahmed shows us the position he was forced to take when the guards entered.

AHMED AL-SHIBLI (through translator): If you don't stand like this, they'd start beating you with electric rods.

It shocks your brain, your heart, every part of your body.

So immediately you have to put your head against the wall.

You are not allowed to look.

Whoever looks will be taken out.

This means he could spend a day, two days or three days under torture.

SIMONA FOLTYN (voice-over): Ahmed was a former officer in the Syrian army.

He was arrested on suspicion of being sympathetic to the opposition alongside nine others.

Only three got out alive.

AHMED AL-SHIBLI (through translator): I thought I saw death in front of my eyes.

We didn't have hope we'd see the light again.

When I got out and saw the sun, I thought I had been reborn.

SIMONA FOLTYN (voice-over): Amid calls for justice, there's also a yearning for revenge.

AHMED AL-SHIBLI (through translator): In my opinion, we should put those who imprisoned us in the same conditions so that they live through the same suffering, so that they know God is just.

SIMONA FOLTYN (voice-over): The new government has yet to announce how it will deal with the perpetrators.

And what will happen to these prisons, the sites of so much injustice and pain.

For the relatives of those missing, there are more questions than answers.

SIMONA FOLTYN: And one of the main questions that remains is how many people exactly disappeared into Assad's prisons?

The United Nations estimates that number at above 100,000, a figure that may rise now that we have access to these institutions as well.

As the documents that have been found there.

John JOHN YANG: Simona, in your piece which was very compelling, you talked about a future justice and accountability process.

Does anyone have any idea what that's going to look like?

SIMONA FOLTYN: Well, we don't know much yet.

And one of the main questions is who exactly will be brought to account?

Will it only be the high ranking officers who issued the orders, or will a future justice and accountability process also include lower ranking officers and foot soldiers, which is certainly what some of the relatives that we spoke to were demanding.

The sheer undertaking of this is immense.

Let's remember, John, that in Assad, Syria, there were more than a dozen different security and intelligence institutions which employed thousands of people.

We don't know where these people are at the moment.

The institutions have been dismantled.

Presumably they're in hiding.

So it remains to be seen whether we're going to stay, start seeing mass arrests in the coming days and weeks, or whether it will be more of a targeted and selective process.

JOHN YANG: Simona, it's just been a week since we saw pictures of Syrians celebrating the fall of the regime.

Now one week on, how are they feeling?

SIMONA FOLTYN: Well, here in the capital, Damascus, we have seen a mix of joy and cautious optimism.

Syrians are certainly happy that Bashar al-Assad is gone.

They feel reassured by the statements that have been cut coming out from Abu Mohammed al-Jolani, the rebel leader turned new ruler of Syria, who has been reassuring Syrians that the new government will be an inclusive one and that there will be coexistence between Syria's different sects.

Now, according to the Constitution, there should be elections within 90 days of the presidential post becoming vacant, and we haven't heard any announcements with regard to that.

So while Syrians are very excited and they're certainly keen to play a role in rebuilding this new Syria, there is a question whether they will be given the space to do so or whether we will transition to a new, perhaps softer form of authoritarian rule.

JOHN YANG: Simona Foltyn in Damascus, Syria, thank you very much.

SIMONA FOLTYN: Thank you, John.