A young couple which attended the College Maisonneuve two years ago was planning to join the Islamic State in Syria, and even began assembling a bomb before leaving.

That, at least, is the prosecution's theory as laid out by the prosecution Wednesday at their trial on terrorism charges.

The Crown said in its opening statement that the RCMP was tipped off to the alleged plot by a phone call over concerns El Mahdi Jamali and Sabrine Djermane were becoming radicalized.

That call came from Djerman's older sister in April 2015, after several of fellow students at College de Maisonneuve had left for the Middle East to join ISIS.

The sister told officers Djermane’s boyfriend had an ISIS logo on his Facebook page.

The RCMP met with the tipster that very day, then with Djermane, and later, with Jamali.

They were arrested several days later.

The Crown said that during their investigation, RCMP officers found notes on how to build a bomb taken from an Al Qaeda propaganda magazine. Police also found bomb-making materials, and suspicious information on phones, tablets, and computers.

The first witness, an RCMP investigator, was cross-examined Wednesday afternoon.

The Crown said its final witness would be an expert on jihad and terrorism who would explain to the jury exactly how Al Qaeda's propaganda machine works and the methods used.

An expert on terrorism will testify during the trial to highlight the importance of a man named John McGuire, an ISIS recruit who once circulated propaganda videos, urging supporters to join the Islamic State and fight, or stay at home and carry out terrorist acts.