I think this is kind of interesting: RCMP Behind Bomb Material, in the sense that they sold it to them: "Investigators controlled the sale and transport of three tonnes of ammonium nitrate in an undercover probe of an alleged homegrown terrorist cell". ...

It's still unclear how the group of suspects is connected and police yesterday offered few details of its alleged activities. But sources close to the investigation told the Star that the investigation began in 2004 when CSIS began monitoring fundamentalist Internet sites and their users.

They later began monitoring a group of young men, and the RCMP launched a criminal investigation. Police allege the group later picked targets and plotted attacks.

So they've been watching these people for two years. Then they sell them a truckload of ammonium nitrate? Good old-fashioned police work!