1. “Active shooter 888 Bestgate please help us.”

At least five people were killed and others were injured when a gunman shot through the glass door at the Capital Gazette newsroom in Annapolis, Md. Journalists inside live-tweeted the attack, including the intern quoted above.

A suspect was in custody and being interrogated, the county executive said.

In New York City, the police deployed officers to protect news outlets. And newsrooms, including ours, waited for a clue as to the gunman’s motive.