The rain was relentless the night Cherwen Polo turned 38, transforming his slum into a slurry of mud and garbage. Water leaked through his corrugated tin roof. Inside, he and four friends had been celebrating for hours, drinking late into the night.
There was a knock at the door. It was the police.
Moments later, they shot and killed Polo and three of his friends.
The raid on Aug. 14, 2016, was business as usual for the Philippine police, who have killed an estimated 3,800 suspected drug dealers and users since that summer in a brutal but popular campaign waged by the president, Rodrigo Duterte. As is typical in such cases, police said that the operation...