Filipinos were forewarned. As a candidate, Mr. Duterte vowed to rid the country of drugs and crime in six months. As president, he has guaranteed a pardon to any police officer who killed people in the line of duty, and said that human rights do not apply to drug addicts because they’re not human. To set a good example, Mr. Duterte boasted of shooting suspects dead himself.

His rhetoric and policies have yielded dramatic results. More than 7,000 people have been killed, while the police point to over 43,000 arrests and the surrender of nearly 80,000 drug pushers and more than 1.1 million users. Crimes like theft, carjacking and cattle rustling have collectively dropped 42 percent. But murder has spiked 51 percent — the consequence, according to a recent report by Amnesty International, of an “economy of death,” resulting from corruption, police abuse and pressure for results that have victimized society’s poorest.

A nightly vigil is kept by a group of local and international reporters, documentary filmmakers and photographers. They call themselves “night crawlers,” and they shadow the police who are armed with lists of alleged users and the mandate of door-to-door visits.

These night crawlers wait for word from radio reports, text messages from funeral homes, calls from colleagues and tips from sources within the police force (though tips have become rare since the media brought international attention to the killings). Authorities are now more guarded, and often the only tip-off reporters receive is the departure from the precinct of “scene of crime” officers. As soon as their van leaves, a convoy of journalists gives chase, lights flashing and horns blaring, on a white-knuckle race through the streets of Manila as calls are made to sources in the area in an effort to find the location and beat investigators to it. Crime scenes have reportedly been altered, official statements often contradict witnesses, and the families of victims have accused police of intimidation.

Image A suspected drug dealer killed in October in the San Francisco del Monte neighborhood of Quezon City, Philippines. Credit... Daniel Berehulak for The New York Times

Media scrutiny has changed the way both murders and investigations are conducted. In recent months, killings have gone from the streets and into the privacy of homes. Police cordons are now established farther out from the scene, to ensure distance from photojournalists’ cameras. Witnesses fear reprisals from authorities. Police officers hasten bodies to hospitals, which journalists cannot enter, clearing away crime scenes before they can be documented.