It is very odd.
First, good on the Prime Minister for calling it Terrorism, right off the hop. We get tired of "Oh, well ... he's deranged ... his father used to beat him" yada, yada, yada.
Shooting up anyone's house of worship is Terrorism and nothing else.
The suspect / witness screw up is bizarre. It appears that the Sûreté du Québec arrested the witness who made the 9-1-1 call, like the Keystone Cops that they are known to be. They also arrested a suspect shooter that apparently still had his weapons but gave up without a fight.
So they have two guys ... one a witness and one a suspect. One is a Moroccan Muslim and the other is a French Quebecer. The thing is, the Sûreté is not saying which is which! If the witness is the Arab ...entirely plausible in an attack on a mosque ... and the attacker is some white supremist Quebecois ... not out of the question, the outcome is entirely different than if the attacker is a Muslim terrorist and the witness is a local. Either way , it is an act of terrorism but depending on who did what to whom, the conclusions and outcome are utterly different.
Canada has been lucky to mostly escape this sort of horror, up to now. But it's so ambiguous, you see! Even when we get the "truth" of the matter, it is likely to remain so. May you live in interesting times, indeed!