Hersi was arrested at Toronto’s Pearson airport in March 2011 as he was about to leave for Cairo. The investigation began when a dry-cleaner found a USB memory stick in Hersi’s security guard uniform that contained a book on bomb-making. An undercover police officer befriended Hersi with the cover story of a fellow Somali-Canadian that wanted to join the terrorist group Al Shabab.
Mohamed Hersi is the first person in Canada to stand trial for attempting to join a foreign group classified as a terrorist organization. Hersi arrived in Canada as a four-year-old refugee with his mother after they fled the Somali civil war. As an adult he said his goal was to live in a Muslim country.