DAPCHI, Nigeria — When he heard the gunfire, the guard ran outside the all-girls boarding school and saw camouflaged vehicles barreling toward the gate. Thinking they were Nigerian military troops, he rushed toward them.
“Have you heard the gunshots?” Ali Gambo, 70, the unarmed guard, asked the men inside the truck. “What’s happening?”
Three men dressed in army fatigues and turbans jumped down from the vehicles, threw Mr. Gambo to the ground and pointed a gun at his head.
“We are Boko Haram,” Mr. Gambo recalled him saying. “We are here for your students.”