But a photo of the corpse showed severe bruising, and an autopsy confirmed that he had died of blunt force trauma. Inmates later said Mr. Argoncillo had been beaten by other prisoners, and that he had lain on the floor for several hours before being brought to a hospital. Two inmates have been charged with his murder.

Director General Oscar Albayalde, chief of the Philippine National Police, fired some officers who were involved in highly publicized incidents, but he said the crackdown would continue.

After the backlash against the campaign began, Mr. Duterte said that arresting loiterers was “foolish” and that he had not ordered the police to do so. He said he had merely told them to break up their gatherings. (The police, who had been calling the campaign Operation Loiterer, promptly changed its name.)

Mr. Diokno, the lawyer, called Mr. Duterte’s backtracking an example of his tactics of obfuscation.

“It just shows the naked truth about the kind of power that he’s wielding. It’s not a power based on law but a power based on fear and violence,” Mr. Diokno said, warning of “dark days” ahead.

“I think you can expect more repression, more confusion, more contradictory statements from the president,” he said. “To the point that even his own people will not be sure what they should be doing.”