03/09/2014 08:08 BST | Updated 01/11/2014 05:59 GMT

Joining ISIS: Hamzah Parvez and Mohammed Nasser

On the 15th of May, Hamzah Parvez and Mohammed Nasser left for Syria to join the Islamic State (IS). They were friends from their days in Holland Park School. According to Hamzah's family they had become increasingly close over the last few years especially as both began to practice their faith.

Hamzah Parvez, a BTEC student, had left college and worked in Ibis hotel in Shepherds Bush but left as he became increasingly devout. He didn't want to be involved with the selling of alcohol, something prohibited by Islamic law. His days were spent at home, in the evenings he would meet Mohammed Nasser and friends and they would attend talks and lectures and return home late.

Mohammed Nasser was far more successful academically, after finishing his studies at Sixth Form College at St. Charles, he became a business undergraduate at Roehampton University. His friends and relatives described him as being a joy to be around. A cousin, who wanted to remain anonymous, said he came from a devout family and always knew right from wrong.

The Syrian conflict had a profound impact on the two. Both were moved by the inaction of the international community. Nasser's cousin said that he was always aware of the injustices going on around the world and wanted to make a difference. But they were also influenced by a heady mix of Salafi Jihadi thought as well as Western foreign policy grievances. In his YouTube post Hamzah cites Sheikh Anwar Awlaki, the US cleric believed to be an Al-Qaeda affiliate, as an authority on Jihad. By the time Hamzah arrived in Syria he believed that Muslims shouldn't live in a country that kills fellow Muslims.

Hamzah's parents might not understand it but he believed that it was impermissible for Muslims to live in a non-Muslim country. And so when they begged him to return to the UK once they found out he was in Syria, he confounded them by saying that they should visit him instead. After all IS facilitates for the parents of fighters to visit. In any case he could not return. He believed Jihad was obligatory on every able bodied Muslim. And it was precisely because of this conviction that he deceived them when he left for Syria.

He left on the pretext that he was going on a training course put on by his former employers in Germany. According to a family member they were overjoyed by this opportunity afforded to Hamzah. The family didn't suspect anything except that there were some incidents that in hindsight seemed odd. One time Hamzah's mother bought him a top from Primark which had the American flag stitched on and he refused to wear it because, according to him, it was a symbol of oppression; the flag that had killed so many Muslims around the world. When his younger brother responded jokingly by saying he wasn't going to Germany but a terrorist camp, he went pale and serious.

One of Nasser's friends when he found out they were flying out to join IS tried to dissuade him. He told Nasser that joining IS meant fighting other Muslims and not the root cause, namely President Assad. But Nasser insisted that he would join the latter but with the condition that he be placed with a battalion that only fights Assad.

According to Hamzah's family, they flew out from Gatwick on the 15th of May to Munich, they did not know that Mohammed Nasser was accompanying him. When the family heard nothing from Hamzah, they reported him missing. They asked the police to block his passport but the law did not allow it since Hamzah was an adult. The police said that the two friends were meant to have returned to the UK four days after their departure. Although they did check in as if to return to Gatwick they never got on the plane. They made their way to Turkey and then ended up in a safe house in Gaziantep or Urfa where many IS recruits lay low before crossing over during the night. Once inside Syria, Hamzah Parvez became Abu Hamzah the Pakistani and Mohammed Nasser became Abul'bara the Eritrean.

Their departure had a devastating impact on the families. They were unable to comprehend the motivations of their offspring. They did not hear from them for months. Some went through a deep sense of betrayal because they felt that they had broken their trust and the bonds of filial piety. The silence though was probably because they were undergoing military training. Whenever recruits undergo training there is a communication black out with the outside world.

Later on the two friends were separated and placed in different battalions. Nasser's family only made contact with their son the day before he was killed on the first day of Ramadan. Nasser was killed by a small piece of shrapnel through his head. Hamzah said that many of his comrades had seen dreams of him in paradise. Dreams are considered to be good omens in the Islamic tradition. Nasser's family devastated by their loss left the country for Mecca consoling themselves in pilgrimage. Nasser's cousin and best friend said that the family want to be left alone to deal with the loss of their son.

The Parvez family however, are completely at a loss. On one hand they are torn by worry for their son's safety, and on the other hand they are worried about the repercussions this may have on them. Hamzah once described as lazy by a family member, has undergone profound change. He is actively taking part in building this nascent Islamic state, he works hard and remains in Syria flitting into Iraq where not only has he seen combat but is employed in and around the oil fields, he drives trucks, works the fields as well as carrying out administrative duties. IS it seems have given this ordinary idealistic young man a new lease of life by giving him purpose.

See also the accompanied report for ITV News here