Thanks to mobile phones, Twitter, and instant publishing, you can read all about the latest mass shooting within minutes. But much of what you’re reading, even days afterward, is false. First come the inference-riddled hearsay accounts from confused marginal witnesses. Then come the speculating journalists. Then come the political axe-grinders, cherry-picking reported details to validate their agendas. The latest case is Tuesday’s attack in a shopping mall near Portland, Ore. Here’s how the errors and escalations have played out so far.