JUDY WOODRUFF: The Islamic State declared its caliphate in 2014 in a caliphate across
great swathes of Syria and Iraq.
Now, three years later, ISIS has been routed from most of the land that it once held.
But the destruction and wounds of war will be long-lasting, no more so than for the children
who the extremists sought to brainwash and turn into a next generation of fighters.
They called them the Cubs of the Caliphate.
From Northern Iraq, special correspondent Marcia Biggs reports.
MARCIA BIGGS: Mosul may be liberated from ISIS, but the fear on its streets is palpable.
As some of its almost one million citizens begin to return home, the issue on everyone's
mind is the possibility of a resurgent ISIS.
Throughout the nine-month battle, Kurdish and Iraqi officials tried to root out ISIS
fighters and sympathizers, screening and detaining thousands from the mass of people who fled
the city.
Many of those detained were children, and some were what is called their Cubs of the
Caliphate, seen here in this propaganda footage.
ISIS made the recruitment of children for military purposes routine, sending children
as young as 4 years old to training camps, where they would learn to fight, kill, and
even die for the Islamic State.
AASMUND LOK, UNICEF: They wanted them as young as possible, so they can shape their minds.
MARCIA BIGGS: Aasmund Lok is a child protection specialist for UNICEF.
AASMUND LOK: Some of them are forcefully taken and forced to become fighters.
Some young people have joined for financial reasons.
Breadwinners could have been killed or went missing.
So, some of the young ones had to step up and find ways to support themselves and their
families.
And the majority of the kids in detention are between 15 and 17.
MARCIA BIGGS: Fifteen to 17.
That means, when ISIS came, they were between the ages of 12 and 14.
AASMUND LOK: Yes.
Of those who sits in detention all joined when they were 10, 11, 12.
MARCIA BIGGS: These are just kids.
AASMUND LOK: Just kids.
MARCIA BIGGS: One of those kids was 16-year-old Mahmoud.
He was just 13 when ISIS came to his village.
He says ISIS fighters picked him up from a neighborhood mosque and took him to a training
camp, where he was kept for 45 days.
MAHMOUD, Former ISIS Recruit (through translator): They promised they would give us cars, guns,
and money.
Then they promised that we would go to heaven.
MARCIA BIGGS: And did they give you those things?
MAHMOUD (through translator): No, they didn't give me anything.
MARCIA BIGGS: Mahmoud says the camp was deep in the desert, where children from Turkey,
Iraq, even the United States were put through a boot camp, which included weapons training
and target practice.
Were you good at it?
MAHMOUD (through translator): No, I wasn't good.
I used to keep my right eye open and left one closed, but I was supposed to do it the
other way around.
So, I never hit the target.
MARCIA BIGGS: Punishments were severe, and the indoctrination was so intense that he
says some of the boys even volunteered to be suicide bombers.
After 45 days, ISIS gave the campers a break in their training.
Once home, he says his family forbade him from going back, sending him to a relative's
house to hide.
MAHMOUD (through translator): At the beginning, I was mad.
But then I stopped being angry.
When you first come back from the camp, the ideas stay in your mind.
But, after a little while, you stop believing in the ideas of ISIS.
MARCIA BIGGS: When coalition forces began driving ISIS from Mosul last year, his family
heard that children who had been in training camps were being arrested, and Mahmoud says
he surrendered to protect himself.
MAHMOUD (through translator): If I went to prison and paid my dues, I would come out
more comfortably.
No one could then accuse me of being ISIS.
MARCIA BIGGS: First, he was taken to a jail for processing in the town of Qayyarah.
MAHMOUD (through translator): There was misery there that none of us had ever seen before.
Some people were given no water for four or five days, three days with little food.
Some people tried to eat the plaster off the walls.
One guard whose brother had just died fighting ISIS would come and beat us, and accuse us
of killing him.
MARCIA BIGGS: Do you wish you hadn't turned yourself in?
MAHMOUD (through translator): Yes.
Whenever they would beat me violently, I thought it would have been better had I not surrendered.
Some people were tortured, kicked, and beaten with cables.
They were kept in tires to keep them from moving.
MARCIA BIGGS: He was then sent to one of several jails just south of Mosul, where photography
is now strictly forbidden, but these images surfaced a few months ago.
He says the beatings stopped, but that the conditions remained unbearable.
We went to one of those jails and were allowed to speak to 17-year-old Mohammed.
He was just 14 when he joined is, or Da'esh, as it's also known.
He had only been at the camp for two days when he lost his leg in an airstrike.
He asked us not to show his face, and we filmed him in the dark.
Why did you join Da'esh?
MOHAMMED, Detainee (through translator): ISIS had already killed 12 members of my family.
They killed my brother-in-law and arrested my sister and her child.
My other brother-in-law fled to Baghdad and joined the federal police.
That means we were a wanted family.
If I hadn't joined, I would have been killed.
And, at first, the situation was really good.
They gave us presents and organized games.
They gave us candy.
MARCIA BIGGS: After liberation, he says he also surrendered, thinking he would be treated
better and he could go back to school.
Instead, he's been here for three months, and he has not been able to communicate with
his family.
MOHAMMED (through translator): The condition in the prison is stifling, overcrowded.
There is feces everywhere.
People are sick and have skin diseases.
The conditions are scary here.
It's a nightmare.
Inside the prison, it's a nightmare.
MARCIA BIGGS: What do you think will happen to you?
MOHAMMED (through translator): My fate is not clear.
I don't know.
MARCIA BIGGS: Without our cameras, we were allowed inside the holding cells.
So, we just came out of the prison.
We weren't allowed to film, but let me tell what it was like going inside there.
The stench was incredible, flies everywhere, people stacked person to person to person,
not able to lie down, just sitting up.
We literally had to step over every single one of them.
There are apparently 100 children in there, combined with 300 other men.
The scene in the jail was much like this one.
And we're told some boys can stay in facilities like this for as long as a year.
As we left, we saw the mothers, hoping and waiting for their sons.
Mahmoud served eight months in prison before being released.
His mother, Miriam, says she that for more than two months after his arrest, she had
no idea where he was.
MIRIAM, Mother of Mahmoud (through translator): This was the most difficult period of my life.
It started with ISIS and then continued with the government arresting our children, instead
of letting them go back to school.
MARCIA BIGGS: We spoke to a representative of the local government.
And she says that anyone who joined ISIS is a criminal, but that prison is meant to rehabilitate
the children.
How is detaining them in overcrowded prisons, where, in some cases, they are beaten and
they're held with adults, how is this going to help them?
SUKEINA MOHAMED AL, Director and Women and Children Department (through translator):
That is your opinion, but, actually, my opinion is that it's the role of the government to
guide those people, to reform them.
If we let them out on their own, they could create a new movement.
It's a prison.
These things happen.
Torture takes place, unfairness, discrimination.
Everything goes.
This is prison.
MARCIA BIGGS: Are you afraid that releasing these children will pose a threat, that ISIS
sleeper cells will use them to attack Iraq again?
SUKEINA MOHAMED AL (through translator): One million percent.
We expect that.
I received one kid who was just 9 years old, and he had cut off the heads of three people.
So, you answer me, what am I to do with this case?
MARCIA BIGGS: Not all of the children are a danger to society, and Lok is implementing
psychosocial programs in some of the prisons.
But he can't get into all of them.
He's not had access to this prison or the one that we went
And he says reversing the stigma for those released is also a huge obstacle.
Do you think the families of these children would feel safe to come forward to try to
get help for them?
AASMUND LOK: We have met kids who are not able to stay in touch with their families
because the families don't want to have contact with them because of the association, because
that could potentially put their families at risk.
MARCIA BIGGS: So, where do they go?
AASMUND LOK: Good question.
I don't know.
MARCIA BIGGS: As we drove through Mosul, where the makeshift soccer fields line the streets,
we were reminded of just how many young boys have come of age under ISIS.
AASMUND LOK: What breaks my heart is that some of them may be facing now 10, 15 years
in detention because of the choices they have made.
But, at the end of the day, they're just kids.
MARCIA BIGGS: Just kids in a community and a country that won't soon be ready to trust
them again.
For the "PBS NewsHour," I'm Marcia Biggs in Mosul, Iraq.