In The New York Times, Adam Goldman and Alan Blinder report that the F.B.I. arrested the wife of Omar Mateen, the man who was responsible for the June terrorist attack in an Orlando nightclub that killed 49. The F.B.I. charged her with obstructing an investigation and aiding and abetting by providing material support. Noor Salman says that she was unaware of her partner’s plans to carry out a mass shooting in a show of allegiance to the Islamic State.