The inside story of a wave of assassinations in Yemen, led by former US Special Forces. An investigation by BBC Arabic has found evidence that the United Arab Emirates hired American mercenaries to train Emirati officers to assassinate political enemies in Yemen. It's triggered a wave of killings that continues today and demonstrates the complex role foreign powers are having in Yemen's civil war. Former US servicemen who worked for the company, Spear Group Operations, have spoken to our reporter Nawal Al-Maghafi.The Global Story delivers insights from BBC experts around the world, with Katya Adler. We want your ideas, stories and experiences to help us understand and tell The Global Story. Email us at theglobalstory@bbc.com You can also message us or leave a voice note on WhatsApp on +44 330 123 9480. Today’s episode of The Global Story was made by Neal Razzell and Tom Kavanaugh. The technical producer was Gareth Jones. The assistant editor is Sergi Forcada Freixas and the senior news editor is Jonathan Aspinwall.