Who is Aseel Muthana and how did he become radicalised?
Aseel Muthana was just 17 years old when he left Cardiff to join IS militants in Syria in 2014.
Five years on, ITV News tracked him down in a prison in northern Syria where he is being held- and says he wants to return home.
Aseel's family live in the Butetown area of Cardiff - a multicultural area of the capital with a high Muslim population. Before he left for Syria, Aseel was studying for his A levels at Fitzalan High School.
Efforts by his parents to stop him being radicalised and leaving the country failed. His passport was taken away from him - so he looked elsewhere for help.
In 2016, three men were jailed for helping assist Aseel travel to Syria to join his brother Nasser.
Kristen Brekke, Adeel Ulhaq and Forhad Rahman were jailed for a total of fifteen and a half years.
The court heard Muthana and Rahman exchanged affectionate text messages, including one from Rahman which was said to read: "Radicalise me babe x"
Rahman later introduced his young friend to Ulhaq, who gave help online and used his contacts in Syria to smooth Muthana's entry.
In the months leading up to him leaving for Syria, Aseel filmed himself and Brekke in Cardiff holding BB guns pretending to be on missions in the war-torn country.
'This is the fake jihad life' - Cardiff teen filmed himself and friend pretending to be on missions in Syria
Aseel is heard in the video saying, "If you're watching this, I'm probably dead - or a legend or something."
Aseel was working at an ice cream parlour in the Grangetown area of Cardiff when he first met Brekke.
During a trial at London's Old Bailey, the court heard Muslim convert Brekke obtained a passport for him to allow Aseel to travel abroad.
In 2015, Aseel and Nasser's father Ahmed, who lives in Butetown, spoke out saying he feared his sons were on the UK government's "hitlist".
He said he felt the police did not do enough to stop Aseel travelling abroad.
Once in Syria, Aseel Muthana is said to have become a prolific recruiter, and he and his brother were added to the United Nations sanctions list in September 2015.
The Sunday Times published a story in 2016 suggesting Nasser Muthana, a "leading Isis recruiter and propagandist" was killed in an air strike in Mosul, Iraq.
Nasser featured heavily in an Isis recruitment video in 2014 with Reyaad Khan, also from Cardiff, where he urged Muslims in the West to join their fight.
Before he left for Syria, Nasser was described as a "promising medical student". All three attended the Al-Manar community centre and mosque in Cardiff.
In a previous interview, Aseel always insisted his local mosque had "no involvement" in his radicalisation, and it was his older brother who had a greater influence over him.
"None of them radicalised me. My older brother taught me a lot about jihad when I was young. I was always pro-jihad but didn’t approach the local imams or my parents because we knew it would brought us trouble."