Slow down, take a breath and try to learn something. Red flag is a noun. Its not a verb. It's not an action nor does it imply one as you can't seem to let go of.
If you want to have a discussion about what could or should have been done to possibly prevent this shooting, especially given all the red flags this girl presented, that's a different question. Get it now? Good. Have a great night.
red flag
noun
- A warning signal.
- Something that demands attention or provokes an irritated reaction.
- A cue, warning, or alert; a sign or signal that something is wrong.