Possession of firearms by non-resident visitors is legal, even if they are residents of Canada and an Iranian national. That does not mean he entered the country illegally. Whether he purchased them here or if they belong to someone else has yet to be determined.
I'm afraid I have to ageree with Vendome on this.
Possession/purchase is legal with qualifications; not as an absolute, last time I looked at the law. That is why I wrote, "The crime leading to confiscation is most likely illegal purchase/possession by a nonresident alien, but the 'false staements' charge was enough to hold him while the rest gets investigated.
Temporary confiscation is standard police procedure in most cases involving alleged weapons violations.