I met Saron, a 16-year-old girl from Eritrea, last summer in an abandoned industrial facility a few miles east of Tripoli. Along with more than 700 other Eritrean refugees, she had been captured earlier that day by one of the many militias that have carved out a zone of influence in Libya's fractured society.

The refugees were fleeing Africa's most repressive dictatorship, hoping to catch a boat to Europe with one of the countless smugglers who ply the route on overcrowded, ill-equipped boats.

Back in Eritrea, Saron would soon have been forced by law to end her education, enrol in military school and serve for an indefinite period of time in the Eritrean army. "The reason I left my country was there is no future in there. There is no hope," she told me, while I was working on a film for VICE News. "You just become a soldier, you go [to] war. I want to reach Norway, obtain citizenship, study human rights, and change my country."

Watch the VICE News documentary: Detained by Militia: Libyan's Migrant Trade

But like many other refugees seeking to pass through Libya, Saron and her fellow captives became human commodities, pawns in a game of power and wealth played by Libyan militias.

To get to Tripoli, they had traveled for eight days, at night in vehicles and kept in cages during the day. Their food and water had run out on the fourth day. After finally nearing the capital and gathering at a farm, waiting for a boat to be made ready to travel to Italy, the group had been captured by the powerful militia Libya Dawn.

Whilst we talked, she took my notebook and begun to write, attracting the attention of a nearby guard. He rushed over, brandishing his Kalashnikov, and interrupted us aggressively.

Saron is no more than 5 feet tall and slightly built, but she looked him coolly in the eyes.

"I'm writing down my brother's telephone number so he can call him and let my family know that I'm alive," she said. "Is that a problem?"

Saron, an Eritrean teenager, spoke to VICE News from a makeshift prison where she was being detained by Libyan militia

Despite his gun, and the scars of a four year civil war, the guard could only stammer a reply.

According to one of the militia commanders, who didn't want to be named, they had received an offer from a gang, wanted to buy the migrants for $2 million for use as slaves and fighters. 

But for the moment, the commander said, they had refused, preferring to keep hold onto the hostages as a card to play with the new unity government, which is expected to be formed shortly. The many militias controlling Libya are attempting to present themselves as a credible force taking good control of their territory and the illegal migration taking place within it — hoping to be granted legitimacy and funding from authorities as a result.

I had to leave Saron there. When I spoke to her next, she had seen things that no teenager should have to see.

* * *

On April 18, European political and public opinion was shaken by the news of the most deadly day in the Mediterranean since World War II, when an estimated 850 migrants died following the capsizing of their boat off the Libyan coast.

In May, it emerged that the European Union had drawn up plans for military attacks on smuggling networks in Libya. A draft resolution prepared by Britain reportedly called for the "use of all means to destroy the business model of the traffickers".

Soon after, the Islamist government in Tripoli declared its intention to fight irregular migration from its territory, and begun a campaign to represent itself as an enemy of the people smugglers. They promised armed patrols and the deportation of migrants.

The numerous militias that control Libyan territory and are widely believed to be involved in the human traffic business, understood this as their cue to increase their political standing and begun to "arrest" illegal migrants, or sometimes just black people.

One of these was the militia holding Saron. It had previously allied with Ansar al Sharia, the militia linked to the September 2012 attack on the US diplomatic mission in Benghazi. Having been expelled from Benghazi a few months ago, they had relocated to Tajoura, east of Tripoli.

Related: Fortress Europe: The Billion Dollar Machine That Keeps Migrants at Bay

Like other militias who have taken to "arresting" migrants, they were not acting under the oversight of the Interior Ministry, or with any formal legal authority.

Yet armed groups in Libya now believe that if they are able to stop migrants arriving in Europe, whatever means they use, they will become a de facto partner of Europe, thus gaining legitimacy and power.

This belief is based on their experience. The European Union collaborated with the regime of Muammar Gaddafi, providing aid so that he would prevent the flow of migrants across the sea. They did so despite the fact that the Libyan security services were well-known for their abuse of human rights and the fact that Libya is not party to the 1951 Convention relating to the Status of Refugees.

The British plans to take military action against smugglers never came to anything, and likely were never practical. But the episode gave the cover of legitimacy to militias detaining and holding refugees, even without legal due process.

* * *

One night after VICE News left the makeshift prison, the guards got drunk, Saron later told me. She and a few other women tried to take advantage and escape. For many of them, it turned out to be a bad idea.

For some reason, some of the other detainees sounded the alarm and guards rushed set out in pursuit, shooting to kill.

Luckily, none were harmed. Some of the escapees got away, Saron and a few others laid down in the dirt so as not be shot and were recaptured.

Amid the chaos, a group of Eritrean men thought they saw their own chance and tried to escape as well. Militiamen chased them too. Two were gunned down, another two were arrested.

Saron, the youngest of the escapees, was tied and forced to watch as the two men and the other women were tortured with a stick with nails attached to it. In front of all the detainees, a militia member pressed a pistol to the head of each of the two men who tried to escape and shot them dead.

Related: More Children Are Making the Dangerous Journey to Europe Alone

Following the mass escape attempt, the militia decided to sell 26 of the Eritreans, including Saron, to a smuggler for 26,000 Libyan dinar ($19,000).

The smuggler made the migrants pay back the 1,000 dinar for which they were each purchased, as well as the price of the boat trip to Europe and the costs of an array of other "services," such as accommodation, transport to and from safe houses, life jackets and telephone communications. In total Saron's family paid $2,800.

Saron was transferred to the port of Sabratah where she and more than 500 other migrants were loaded onto a wooden boat. The loading took two hours and nobody was at pains to hide it, Saron later said.

Libyan men from another militia were guarding the group at the port and followed the boat in three dinghies, giving instructions along the way, until the boat reached international waters.

Neither Saron nor I know what happened to the other Eritrean refugees who unluckily found themselves captive in that old industrial facility outside Tripoli. We cannot know, but what is likely is that for many of them their journey did not have a happy end. If their fates matched those of other refugees seeking to reach Europe, some were sold as slaves, some died of sickness, some were shot, and some drowned at sea.

They came from Eritrea, one of the most cruel dictatorships in the world, where according to the UN, the use of extra-judicial killing, torture, indefinite military conscription and forced labour is systemic.

They were fleeing to the European Union, which agreed in April a $353 million development package with the Eritrean government, reportedly in an attempt to discourage emigration.

As for Saron, she made it.

She left her home and her country at 16 years old for an almost 4,000 mile journey, accepting that death was a possible consequence of her migration, of her determination to live in a free country.

"We can't get out of our country legally — it's always illegal and they can kill you," she said. "So it was okay for us to cross the sea. We know a lot of people died there. But we accept it as Eritreans, because our government can't help us."

I met Saron, a 16-year-old girl from Eritrea, last summer in an abandoned industrial facility a few miles east of Tripoli. Along with more than 700 other Eritrean refugees, she had been captured earlier that day by one of the many militias that have carved out a zone of influence in Libya's fractured society.

The refugees were fleeing Africa's most repressive dictatorship, hoping to catch a boat to Europe with one of the countless smugglers who ply the route on overcrowded, ill-equipped boats.

Back in Eritrea, Saron would soon have been forced by law to end her education, enrol in military school and serve for an indefinite period of time in the Eritrean army. "The reason I left my country was there is no future in there. There is no hope," she told me, while I was working on a film for VICE News. "You just become a soldier, you go [to] war. I want to reach Norway, obtain citizenship, study human rights, and change my country."

Watch the VICE News documentary: Detained by Militia: Libyan's Migrant Trade

But like many other refugees seeking to pass through Libya, Saron and her fellow captives became human commodities, pawns in a game of power and wealth played by Libyan militias.

To get to Tripoli, they had traveled for eight days, at night in vehicles and kept in cages during the day. Their food and water had run out on the fourth day. After finally nearing the capital and gathering at a farm, waiting for a boat to be made ready to travel to Italy, the group had been captured by the powerful militia Libya Dawn.

Whilst we talked, she took my notebook and begun to write, attracting the attention of a nearby guard. He rushed over, brandishing his Kalashnikov, and interrupted us aggressively.

Saron is no more than 5 feet tall and slightly built, but she looked him coolly in the eyes.

"I'm writing down my brother's telephone number so he can call him and let my family know that I'm alive," she said. "Is that a problem?"

Saron, an Eritrean teenager, spoke to VICE News from a makeshift prison where she was being detained by Libyan militia

Despite his gun, and the scars of a four year civil war, the guard could only stammer a reply.

According to one of the militia commanders, who didn't want to be named, they had received an offer from a gang, wanted to buy the migrants for $2 million for use as slaves and fighters. 

But for the moment, the commander said, they had refused, preferring to keep hold onto the hostages as a card to play with the new unity government, which is expected to be formed shortly. The many militias controlling Libya are attempting to present themselves as a credible force taking good control of their territory and the illegal migration taking place within it — hoping to be granted legitimacy and funding from authorities as a result.

I had to leave Saron there. When I spoke to her next, she had seen things that no teenager should have to see.

* * *

On April 18, European political and public opinion was shaken by the news of the most deadly day in the Mediterranean since World War II, when an estimated 850 migrants died following the capsizing of their boat off the Libyan coast.

In May, it emerged that the European Union had drawn up plans for military attacks on smuggling networks in Libya. A draft resolution prepared by Britain reportedly called for the "use of all means to destroy the business model of the traffickers".

Soon after, the Islamist government in Tripoli declared its intention to fight irregular migration from its territory, and begun a campaign to represent itself as an enemy of the people smugglers. They promised armed patrols and the deportation of migrants.

The numerous militias that control Libyan territory and are widely believed to be involved in the human traffic business, understood this as their cue to increase their political standing and begun to "arrest" illegal migrants, or sometimes just black people.

One of these was the militia holding Saron. It had previously allied with Ansar al Sharia, the militia linked to the September 2012 attack on the US diplomatic mission in Benghazi. Having been expelled from Benghazi a few months ago, they had relocated to Tajoura, east of Tripoli.

Related: Fortress Europe: The Billion Dollar Machine That Keeps Migrants at Bay

Like other militias who have taken to "arresting" migrants, they were not acting under the oversight of the Interior Ministry, or with any formal legal authority.

Yet armed groups in Libya now believe that if they are able to stop migrants arriving in Europe, whatever means they use, they will become a de facto partner of Europe, thus gaining legitimacy and power.

This belief is based on their experience. The European Union collaborated with the regime of Muammar Gaddafi, providing aid so that he would prevent the flow of migrants across the sea. They did so despite the fact that the Libyan security services were well-known for their abuse of human rights and the fact that Libya is not party to the 1951 Convention relating to the Status of Refugees.

The British plans to take military action against smugglers never came to anything, and likely were never practical. But the episode gave the cover of legitimacy to militias detaining and holding refugees, even without legal due process.

* * *

One night after VICE News left the makeshift prison, the guards got drunk, Saron later told me. She and a few other women tried to take advantage and escape. For many of them, it turned out to be a bad idea.

For some reason, some of the other detainees sounded the alarm and guards rushed set out in pursuit, shooting to kill.

Luckily, none were harmed. Some of the escapees got away, Saron and a few others laid down in the dirt so as not be shot and were recaptured.

Amid the chaos, a group of Eritrean men thought they saw their own chance and tried to escape as well. Militiamen chased them too. Two were gunned down, another two were arrested.

Saron, the youngest of the escapees, was tied and forced to watch as the two men and the other women were tortured with a stick with nails attached to it. In front of all the detainees, a militia member pressed a pistol to the head of each of the two men who tried to escape and shot them dead.

Related: More Children Are Making the Dangerous Journey to Europe Alone

Following the mass escape attempt, the militia decided to sell 26 of the Eritreans, including Saron, to a smuggler for 26,000 Libyan dinar ($19,000).

The smuggler made the migrants pay back the 1,000 dinar for which they were each purchased, as well as the price of the boat trip to Europe and the costs of an array of other "services," such as accommodation, transport to and from safe houses, life jackets and telephone communications. In total Saron's family paid $2,800.

Saron was transferred to the port of Sabratah where she and more than 500 other migrants were loaded onto a wooden boat. The loading took two hours and nobody was at pains to hide it, Saron later said.

Libyan men from another militia were guarding the group at the port and followed the boat in three dinghies, giving instructions along the way, until the boat reached international waters.

Neither Saron nor I know what happened to the other Eritrean refugees who unluckily found themselves captive in that old industrial facility outside Tripoli. We cannot know, but what is likely is that for many of them their journey did not have a happy end. If their fates matched those of other refugees seeking to reach Europe, some were sold as slaves, some died of sickness, some were shot, and some drowned at sea.

They came from Eritrea, one of the most cruel dictatorships in the world, where according to the UN, the use of extra-judicial killing, torture, indefinite military conscription and forced labour is systemic.

They were fleeing to the European Union, which agreed in April a $353 million development package with the Eritrean government, reportedly in an attempt to discourage emigration.

As for Saron, she made it.

She left her home and her country at 16 years old for an almost 4,000 mile journey, accepting that death was a possible consequence of her migration, of her determination to live in a free country.

"We can't get out of our country legally — it's always illegal and they can kill you," she said. "So it was okay for us to cross the sea. We know a lot of people died there. But we accept it as Eritreans, because our government can't help us."