Why did they do this?

I hope we find out more about the Ontario terrorism plot soon, because here's something already that I don't understand.
From the Globe and Mail photo gallery, here is a photo from Saturday's press conference:


Globe and Mail cutline: Items are shown on display during a press conference in Toronto. The bag of fertilizer, top, was not seized during the raid and was there for display purposes only.

Emphasis mine.
So apparently someone from the police department went out and bought a bag of ammonium nitrate fertilizer to put on display at the press conference?
Why would they do this? So that reporters would know what fertilizer looks like? Because someone thought that all the guns and electronic gear and cell phones didn't tell enough of a story?
One of the Toronto Star stories talks about the importance of the case to Canadian law enforcement:

The case is critical for Canada's international reputation and will be scrutinized worldwide as it works its way through the courts.
There has been cause for skepticism concerning the ability of Canada's intelligence and police services to prosecute security cases. Since 9/11, the majority of high-profile security investigations have ended in international embarrassment, such as the acquittal of suspects in the Air India bombing case and the Maher Arar affair which raised questions about international information sharing, exposed an inexperienced federal police force and left an Ottawa man broken after his deportation, detention and torture in Syria.
Then there was Project Thread, a 2003 joint immigration-RCMP case touted as the dismantling of an Al Qaeda cell, but ending in a routine immigration case that sent Pakistani students home branded terrorists.

So please, folks, if you have confidence in your case, you don't need to be buying a bag of fertilizer to try to make it scarier.