An Afghan boy, who was held as a child sex slave, sits at a restaurant in a unidentified location in Afghanistan

Quivering with quiet rage, Shirin holds a photo of his teenage brother-in-law, who now lives as the plaything of policemen, just one victim of a hidden epidemic of kidnappings of young boys for institutionalised sexual slavery in Afghanistan.

Shirin is among 13 families AFP traced and interviewed across three Afghan provinces who said their children were taken for the pervasive practice of "bacha bazi", or paedophilic exploitation, in Western-backed security forces.

Their testimonies shine a rare spotlight on the anguished, solitary struggles to free sons, nephews and cousins from a tradition of culturally-sanctioned enslavement and rape.

Shirin recalled how his 13-year-old brother-in-law screamed and writhed as he was taken from his home earlier this year by a police commander in southern Helmand.

"When I begged for his release, his men pointed their guns and said: 'Do you want your family to die? Forget your boy'," Shirin told AFP in Lashkar Gah.

"Our boys are openly abducted for bacha bazi. Where should we go for help? The Taliban?"

The heart-wrenching stories, mostly from Helmand but also from neighbouring Uruzgan and northern Baghlan, were revealed after AFP reported in June how the Taliban are exploiting bacha bazi in police ranks to mount deadly insider attacks.

The report, denied by the insurgents, prompted an Afghan government investigation.

AFP is withholding the names of the victims and the accused police commanders as many of the boys are still being held captive.

- 'Crazed with grief' -

A common theme in the testimonies collected from stricken families was that of helplessness. Their boys were mostly abducted in broad daylight; from their homes, opium farms and playgrounds.

Once taken captive, they can be shuffled among police checkpoints, complicating efforts to trace them.

Sometimes they emerge into the open as policemen flaunt their spoils.

For fathers like Sardarwali, the crushed hope of such an encounter is almost too much to bear.

After months of fruitless searching, he caught a glimpse of his kidnapped son in a crowded marketplace in Helmand's Gereshk district.

The child -- a slight boy who loved nothing better than playing with his siblings -- was dressed in a fine embroidered tunic and wore a bejewelled skull cap.

Sardarwali was desperate to reach out to his son, to hold him -- but did not dare approach the bevy of policemen that surrounded him.

"I watched him disappear into the distance," Sardarwali said.

"His mother is crazed with grief. She cannot stop crying: 'We have lost our son forever.'"

Parents' agony of losing a child to sexual slavery is compounded by concerns that in captivity their boys will become addicted to the opiates some are given to make them submissive.

Worse still, many fear they could be taken to reinforce frontlines, where police are suffering record casualties in their fight against the Taliban.

Or -- as one Helmand family shockingly discovered –- get killed in the crossfire as insurgents over-run the checkpoints where they are held.

Still, some families take grim solace in the knowledge they are not alone. Their villages are full of bacha bazi victims, many discarded when their beards begin to show.

- 'Unconscionable' -

Bacha bazi has seen a chilling resurgence in post-Taliban Afghanistan, where it is not widely perceived as homosexual or un-Islamic behaviour.

Young boys dressed effeminately have an ornamental value in a society where the genders are tightly corralled. Their possession is a mark of social status, power and masculinity.

The practice has spurred a violent culture of one-upmanship within police ranks, as officers jealously compete to snatch the most beautiful boys, said a former top Helmand security official.

"Often the only escape for enslaved bachas is to make a deal with the Taliban: 'Liberate me and I will help you get my abuser's head and weapons'," the official said, referring to insider attacks.

The Afghan government has said it has zero tolerance for child abusers in security ranks.

But Uruzgan government spokesman Dost Mohammad Nayab acknowledged nearly every provincial checkpoint had a bacha. He fears any move to extricate them could see angry policemen abandoning their posts, paving the way for the Taliban.

"It is difficult to separate policemen from their bachas in this security situation," Nayab said, explaining that police serve as a pivotal first line of defence against insurgents.

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