It's suspicious and fear propaganda because they called it a "Mass Casualty Incident" before they even reported about anybody getting shot.

To me it looks like they were withholding information to make it seem scarier. I read 6 articles that were updated 2 hours after your post and none of them said 3 people were shot. So someone knew what was happening because you heard that info but they stopped spreading it around so they could have their fear porn.