One of the most efficient tools in fighting terrorism is to go after what hurts terrorist organisations the most — their finances. In that respect, the FBI has documented much of Hezbollah’s finances and many of its illegal activities, such as drug and human trafficking. Most times, however, links are hard to prove. Tracking down the money trail is not easy. The BBC has revealed that, in 2015, Qatar paid approximately $1 billion to the most dangerous of Iraqi terrorist groups, Kata’ib Hezbollah — a pro-Iranian proxy similar to its namesake organisation in Lebanon. The group had taken hostage 28 Qatari nationals, including two relatives of the Qatari foreign minister. “The payment was ostensibly made to set hostages free but, make no mistake, this was terrorist financing plain and simple,” said Sir Ivor Roberts, a member of the European Advisory Board of the Counter Extremism Project. “It was a direct transfer of funds knowingly made to support the activities of some of the most dangerous terrorists in the world. Kata’ib Hezbollah collaborates with the Islamic Revolutionary Guard Corps’ al-Quds Force and with Iran-backed Hezbollah in Lebanon. Some of the funds made their way to a number of other terrorist groups, including the infamous al-Nusra Front.”