Mohamed Hersi, the first man ever convicted in Canada of trying to join a terrorist group, should get the toughest penalty on the books, Crown lawyers said today at his sentencing hearing.

Federal prosecutor James Clark urged an Ontario Superior Court judge to condemn Hersi to 10 years in prison to set an example.  

"Canada has an international obligation to prevent the exportation of terror," Clark said in court in Brampton, Ont.

Hersi's defence counsel Paul Slansky, who has already pledged to appeal, said his client should get three to four years, calling him "youthful and immature."

Hersi was found guilty by a jury last month of attempting to participate in a terrorist group and of counselling someone to participate in a terrorist group. The Crown contended he was trying to join the Somali militant group al-Shabaab, which Canada deems a terrorist entity.

Each crime can incur a maximum sentence of five years in prison. Under the terrorism provisions of the Criminal Code, any sentences must be served consecutively.

Dry cleaners raised alarm

Hersi is the first person to stand trial in Canada for offences related to the Criminal Code's Section 83.18, which makes it illegal to "knowingly participate" or "knowingly contribute" to "any activity of a terrorist group for the purpose of enhancing the ability of any terrorist group to facilitate or carry out a terrorist activity."

At trial, the prosecution said the 28-year-old, who was working as a security guard, intended to travel onward to Somalia to join al-Shabaab when he was arrested at Toronto's Pearson airport in 2011 bound for Cairo.

Hersi denied the allegations, saying he was going overseas to study Arabic for several months.

Hersi landed on police radar after a dry-cleaning shop discovered a USB key containing a copy of The Anarchist Cookbook, a 1970s manual for making explosives, as well as a Department of National Defence document in his work uniform. His employer reported it to authorities, who sent in an undercover agent to befriend and spy on Hersi.

Over many months, the undercover officer and Hersi hung out together, attended a Raptors basketball game and had frequent discussions that turned to politics, Somalia and al-Shabaab.

The police officer testified that Hersi told him he was planning on going to the East African country to join the militant group.

When Hersi testified in his own defence, he said it was the officer who announced an intention to join al-Shabaab.

The defence contended Hersi was entrapped by the undercover officer, and though he was a big talker, his comments were taken out of context and he never intended to become a jihadist.

Judge Deena Baltman will issue her sentencing decision July 24.