1. Baffled investigators hope that Marilou Danley, who was in the Philippines when her boyfriend, Stephen Paddock, killed 58 people and injured hundreds in Las Vegas, can help explain what drove him to become a mass murderer.

F.B.I. agents met Ms. Danley when she returned to the U.S. late Tuesday. President Trump visited Las Vegas, lauding the efforts of emergency workers and doctors. And leaked photos showed the arms cache inside the hotel room. Here’s the latest.