You’re talking about being found guilty of the crime. You can definitely be arrested for making a statement that in the context was a terroristic threat, and be found not guilty of the crime.

Her arrest was absolutely warranted. Her statement could easily mean that she planned on opening fire on the employees. Not taking that seriously in a country where mass shootings happen almost daily is very stupid.

We also don’t have all of the facts on the case. The police don’t release all of the details of their cases before trial.