More than 7,000 people have been killed in the Philippines’ bloody “war on drugs.” New Human Rights Watch research finds that the killing campaign against suspected drug users and dealers, openly encouraged and applauded by President Rodrigo Duterte, is effectively a war on the urban poor that could amount to crimes against humanity. Human Rights Watch’s emergencies director, Peter Bouckaert, has made two trips to the capital, Manila, to document this unprecedented mass wave of killings. Stephanie Hancock asked him how Human Rights Watch was able to track the police killing squads.