How Boko Haram is turning girls into weapons-Brent Swails and David McKenzie.

The question was always the same, she says. So, too, was the answer.

"They came to us to pick us," Fati recalls. "They would ask, 'Who wants to be a suicide bomber?' The girls would shout, 'me, me, me.' They were fighting to do the suicide bombings."

Young girls fighting to strap on a bomb, not because they were brainwashed by their captors' violent indoctrination methods but because the relentless hunger and sexual abuse -- coupled with the constant shelling -- became too much to bear.

They wanted a way out, she says. They wanted an escape.

Fati, 16, whose name has been changed to protect her identity, pauses and grabs the three gold bracelets around her wrist. They're a gift from her mother, her only connection to home after she became one of hundreds of girls kidnapped by theworld's deadliest terror group, which forced them to marry its fighters.

Fati was kidnapped in Nigeria in 2014 and taken to a Boko Haram camp in the Sambisa Forest.

"It was just because they want to run away from Boko Haram," she said. "If they give them a suicide bomb, then maybe they would meet soldiers, tell them, 'I have a bomb on me' and they could remove the bomb. They can run away."

There was no escape for Fati when fighters from Boko Haram descended on her village in northeast Nigeria in 2014. Her future "husband" was carrying a gun, and Fati's parents had already spent a precious 8,000 naira (roughly $40) to smuggle her two older brothers to safety. There was nothing they could do.

"We said, 'No, we are too small; we don't want to get married,'" Fati recalls. "So they married us by force."

After he raped her for the first time, Fati's abuser gave her a wedding present -- a purple and brown dress with a matching headscarf that she would wear for the next two years while under his control, whisked from hideout to hideout in order to evade Nigerian authorities.

MORE: 9 things to know about Boko Haram

She says she met girls even younger than her in Boko Haram's stronghold in the Sambisa Forest, kidnapped from their families to be married off, imprisoned and abused by their self-proclaimed "husbands."

Fati's gold bracelets, a gift from her mother, are her only connection to her old life.

"There were so many kidnapped girls there, I couldn't count," Fati says.

Among them, she says, are some of the more than 270 schoolgirls from Chibok, Nigeria, whose kidnapping in April 2014 shocked the world.

The social media campaign #BringBackOurGirls gave many people their first glimpse into Boko Haram's targeted abuse of women and girls. But recently the group has embraced a sickening new tactic.

Alarming new statistics released by UNICEF show a dramatic increase in the use of children as bombs in four countries -- Nigeria, Niger, Chad and Cameroon -- where Boko Haram has waged its campaign of terror in the past two years.

The estimated number of children used in bombing attacks has skyrocketed from four in 2014 to 44 in 2015. UNICEF says that three quarters of all child bombers are girls.

As the number of children involved in attacks has risen, a newly formed multinational coalition has been putting pressure on the ISIS-affiliated group like never before.

Fati's story reveals a terrorist organization that is demanding more and more from its captives as its decisions become increasingly fueled by desperation.

The market in Maroua, Cameroon was bombed in July. "Since that day, when I see a young lady or girl who I don't know, I am afraid," says one vender.

Sambisa, once thought to be Boko Haram's impenetrable, even cursed stronghold, is under attack, the target of relentless aerial bombings and raids by the Nigerian military.

"There were always bombs and bullets coming from the sky," Fati recalls. She feared the bombings as much as she feared her captors.

"All of the girls were so frightened. All of them, they always cried and the men raped us," Fati said, remembering her time spent in Sambisa. "There is no food, nothing. The children, you can count their ribs because of the hunger."

Fati says the bombing runs over the Sambisa killed many of the captives, including some of the Chibok girls. But the raids over the past year have also freed hundreds of women and girls, including Fati, who was picked up by the Cameroonian army after her captors defected and tried to flee across the border.

Fati is now in the relative safety of the Minawao refugee camp in Cameroon. When Boko Haram started raiding the border towns, Nigerians ran here, desperate for food and safety.

The camp formed around them, white tents dotting the dusty ground in this growing city of sorts, already double the size of what it was designed to be.

What they've found is a society turned upside down -- a place where girls are viewed with suspicion, rather than embraced.

"We can have all the guns in the world," said Cameroonian Army Col. Mathieu Noubosse. "They are using girls as young as 8."

The colonel's outpost sits on a rocky embankment overlooking Nigeria. The road below extends toward Maiduguri, Borno State's capital and the birthplace of Boko Haram.

Gwoza, once a stronghold of the group and where Fati spent several weeks, is visible from the sights of the soldiers' machine guns. The worry now, as the coalition continues to notch up military victories, is that Boko Haram will continue to pivot towards the use of young girls as their weapon of choice.

Noubossa says girls make for ideal suicide bombers. The devices can be hidden away under their long veils or in baskets on top of their heads. He says the devices are often remotely detonated. The most vulnerable people in this society are now becoming the most feared.

"These are victims," says UNICEF's Cameroon Country Director Felicity Tchibinda. "But they are being viewed in suspicious ways, and we need to change that narrative. There are long-term consequences if we don't. We'll lose the trust between communities and victims and the authorities that are supposed to protect them."

In Minawao, changing the narrative involves campwide advocacy programs and protection for girls such as Fati.

Vigilantes at a checkpoint outside Baigai, Cameroon say Boko Haram's tactics have changed the way they perceive strangers.

Here, the label of Boko Haram wife can carry serious consequences.

"It's a double tragedy," says UNICEF protection officer Loveline Ndam. She says girls are rescued from terror only to be ostracized by their communities.

Spread out at the foot of scrub-covered mountains, the camp is just beyond the red zone of frequent Boko Haram attacks, but on the other side of the hills, small pockets of fighters operate.

"A year ago, the humanitarian situation was clearly worse in Nigeria. Today, it's the same (across the border), same level of crisis," says one senior Western diplomat.

Security officials say that Boko Haram has infiltrated the camp, but what refugees fear the most is escaped abductees such as Fati.

"If we see a strange girl, she may be a suicide bomber," says Mohammed Amodu, a refugee leader. "Perhaps their mind is with Boko Haram."

It's a sentiment that permeates the area where Boko Haram operates.

Fasumata left everything behind to flee Boko Haram. She feels lucky.

Fasumata, a recently arrived refugee, says when the fighting came to her village, she hid for days under mattresses with her children, unable to move until there was a lull in the fighting. When the shooting stopped, she picked up her children and ran.

"Everyone was scared, no shoes, no nothing," she recalls. "Everyone was running for their lives."

Still, she considers herself lucky. She made it to Minawao without getting caught by Boko Haram. She had heard the stories even when her village was still safe from the conflict.

"If they see someone who escaped from Boko Haram, they think they are still with Boko Haram," Fasumata says, "that Boko Haram freed them to do suicide bombs. Not just in the camp, anywhere in Nigeria. People are afraid because everywhere, if you hear 'suicide bomb,' it is a young girl."

"It is terrible what Boko Haram is doing," Fati says.

Fati, meanwhile, is simply grateful to be alive. On the last day of March, she managed to get in touch with her mother by phone after she found a refugee from her same village in camp.

It took two days for her mother to get to Minawao.

"She had to collect money from people in the village so she could afford to make it here," says Fati. "Now that I have escaped, I thank God, and I am always praying to God that I was able to escape."