“A shotgun casing could be seen on the ground outside the centre.”
No Marty, it’s not a casing, it’s a wad. The case would have a nice shiny brass bit at the bottom.
“A spent cartridge was also visible on the ground.”
stuff.co.nz/national/117491519/reports-of-gunshot-during-incident-at-napier-health-clinic
No Marty it is still a wad, not a spent cartridge.
This is what a shotgun shell casing looks like…