Nidal Hasan sentenced to death by military jury in 2013 for carrying out deadly shooting attack at army base in Texas Donald Trump has approved the execution by US army firing squad of Nidal Hasan, who was sentenced to death for killing 13 people at Fort Hood in 2009, chief Pentagon spokesperson Sean Parnell said in a social media post. Hasan, who was an army psychiatrist, would become the first US soldier to be executed by the US military in more than 60 years.