Since Mr. Duterte has taken his campaign nationwide, more than 600,000 drug dealers and users have turned themselves in to avoid being killed, the authorities say. The result, they say, has been a visible reduction in drug use and petty crime.

Renato Bertes, 49, and Jaypee Bertes, 28, lived with their families in a dark warren of alleyways in Pasay City, a part of greater Manila near Ninoy Aquino International Airport. The eight of them shared a small room and a kitchen area with buckets in place of a sink.

According to the police, the officers chanced upon the Bertes men, out in the neighborhood gambling, on the evening of July 6. They arrested them, found small amounts of shabu in their possession and took them to the police station.

The police declined to discuss the case or release their investigative report, but that document was summarized in a report by the Commission on Human Rights, a copy of which was provided to The New York Times.

According to the commission report, members of the Bertes family and a neighbor told a different story. They said that the police “barged into” their apartment at 11:30 while they were in bed. The officers demanded to know where Jaypee Bertes was keeping drugs and began roughing him up.

This was not the family’s first run-in with the police. Ms. Pimentel-Gana said that according to family members, the police had extracted payments of hundreds of dollars from Jaypee twice before.