Over the weekend, 49 people were shot dead by Omar Mateen – a 29 year old who pledged allegiance to ISIL moments before opening fire in a gay nightclub in Orlando, Florida early Sunday morning. He had been under investigation by the FBI for Islamic threat – but was somehow able to purchase an automatic machine gun and ammunition. We spoke with Security and Terror expert Ross McLean about the shooting and what can be done to prevent it from happening yet again.