Filmmaker Robb Leech sets out to discover why his step-brother, Rich, a white middle-class man from Dorset became a radical Islamist.
Robb first heard of his brother’s conversion in a national newspaper in the summer of 2009. The article said Rich had converted under Anjem Choudary, leader of the radical Muslim group Islam4UK, which was later banned under Britain's anti-terror laws.
In a film that took over twelve months to shoot, Robb sets out to reconnect with his extremist stepbrother and find clues to what led Rich to become Salahuddin.
It charts the brothers' relationship and Robb's attempt to understand why the person he'd once looked up to as a role model could so strongly reject all that his family and the Western world believe in.
As Robb spends time with Salahuddin, he witnesses a very particular phenomenon - the embrace of radical Islamism by young men, many of them white.
Read Robb's blog about the program.
"My Brother The Islamist" (UK Title of this film) is on Facebook, and you can follow @myislamistbro on Twitter. Follow @RobbLeech on Twitter.
Grace Productions for BBC