It was the boy's eyes that haunted Priscillia. He was dressed in full army gear, a red beret, and sunglasses, and he carried an AK-47 automatic assault rifle. He was tall but there was about him a teenage gangliness that gave away his age. Yet it was the eyes that she could not forget.
They met in the stronghold of one of the rebel groups in the Central African Republic. The boy was a child soldier who had been press-ganged into the forces of the Convention of Patriots for Justice and Peace (CPJP) which has been fighting for the past four years to overthrow the government in this former French colony in the heart of West Africa.
Priscillia Hoveyda, 30, is a child protection specialist for Unicef in the wartorn country. She is tasked with the dangerous work of entering rebel territory to try to negotiate with the armed rebels for the release of the children they have abducted or forced into arms.
"As soon as I arrived I saw him," she said. "He looked no more than 15 years of age. I asked him to take off his sunglasses and put down his gun. I saw immediately he was a child. "I asked his age. He was 15. I asked if he wanted to leave the armed group. He said he did, and that he wanted to go back to school."
But the rebel commander would not let the boy go and Priscillia had to leave without him. For the next month, she could not rid herself of the memory of the boy's eyes, filled with pain and mistrust. A month later she went back to the camp.
"I had his name – Assane – and I was determined to get him out." She found the boy and asked if he remembered her. He said "Yes" and said he really wanted to get out. So Priscillia went back to his commander. Although this time she persuaded the man to free the child, his order was countermanded by a more senior rebel. "He surrounded us with five of his men and was shouting, 'You can't take him; he is mine'." She watched the boy's face, which had been smiling at the prospect of release, fall as he put all his weapons back on. She left again.
But still Priscillia could not forget. "His face had been so upset. So the next day I went back. At this point I said, 'We're not leaving unless he comes too'. Sometimes it's one kid who gets to you. And finally they let him come out."
Today i is launching along with Unicef a Christmas appeal to raise money for the release of more child soldiers in the Central African Republic. They are not the only children who have been kidnapped and forced to fight. It is estimated that today some 300,000 children – boys and girls from the age of seven to 17 – are involved in more than 30 conflicts worldwide.
But the problem is acute in the north-eastern region of the Central African Republic, close to the border with Chad. The region is home to a number of rebel army groups that use child soldiers. The most notorious is the Lord's Resistance Army (LRA) led by Joseph Kony which operates across the region from the Central African Republic through Chad and the Democratic Republic of Congo to Uganda and South Sudan.
Rescuing the children is perilous work. But Priscillia Hoveyda, a lawyer who trained in Paris and New York, is motivated by her own background: she grew up in Iran when it was at war with Iraq. "I was able to see first-hand the damage war could cause in society, in a community, on a family and a household, on your friends," she said. "Your whole life is turned upside down."
Keeping a cool head is essential. "I've been in situations in this job where men have been aggressive," she said, "where they tried to intimidate me and my co-worker. But we know before going that this may happen and know we should not back off; if we back off it shows we feel weak and that will spoil the whole negotiation process. So we have to remain calm and focus on the children."
What complicates her negotiations is the number of rebel groups. The two main factions, the Union of Democratic Forces for Unity and the CPJP – which fight one another as well as the forces of the government – also fight the Lord's Resistance Army. All the rebel groups seize children, but most – with the exception of the ruthless LRA – will negotiate with Unicef over the release of children. The skill lies in persuading each side that the other will release its child combatants if they are prepared to do the same.
Negotiating the children's release is only the first step. Unicef then runs transit centres where children who have been released are demobilised, put back in school, and given psychological help and vocational training. They are reunited with their families or resettled with foster carers if their families reject them.
All this work is funded entirely by voluntary contributions. The money raised by the i Christmas Appeal will go to one fund one of these centres in the Central African Republic. Over the next four weeks i will be reporting on the difficulties and challenges of that long and complex process.
In the weeks between identifying Assane and his eventual release Unicef found that the boy's parents were dead but managed to track down his older brother. As Assane walked into Endelei, the town where the nearest Unicef transit centre was based, his brother was there to meet him.
After they had greeted one another Assane turned to Priscillia and said: "I feel like I've come home".