A bit more authoritative source than PJ Media, perhaps:
[RCMP Deputy Commissioner Dwayne] McDonald said [Jessica] Van Rootselaar identified as a female, but was assigned male at birth. She started transitioning about six years ago. She dropped out of school around four years ago.
There seems to be some discrepancy about the name of the shooter. Canadian media identifies him as Jessica van Rootselaar rather than Jesse Strang; however, as this article notes, Strang is his mother's last name. (Perhaps Van Rootselaar is an assumed name?)
Clearly not.
I'd say the media was being a bit obfuscatory as to the "gender identity" of the perpetrator.