article_snippet.sent: Peter Taylor interviews Hussam al-Ahmed, a Syrian photographer, in a special documentary investigating the rise of IS and Families diverse sources of funding .
article_snippet.sent: In BBC Two's one hour special documentary, Peter Taylor reveals how the group have risen to power thanks to a diverse source of funds including oil, ransoms, extortion and theft.  
article_snippet.sent: the group have amassed a war chest of an estimated $2billion.
article_snippet.sent: The programme features the first ever TV interview with IS leader Abu Hajjar and investigates what's made The programme the World’s Richest Terror Army.
article_snippet.sent: This World: it the World’s Richest Terror Army is on BBC2 at 9pm .