MANILA - The killing of teenagers Kian delos Santos, Carl Arnaiz, and Reynaldo de Guzman could be part of moves to discredit the administration's war against drugs, the chief of the Public Attorney's Office said.

The manner by which 19-year-old Arnaiz died particularly raises suspicion, said PAO chief Persida Acosta.

"Kahit sino mag-iisip noon na bahagi ng destabilization. May noble intent ang campaign against drugs...So mag-iisip ng kahit sino, maging pangkaraniwang mamayang Pilipino, na parang may sabotahe dito," she told reporters.

Acosta said the people behind the campaign could be the same people who want to oust President Rodrigo Duterte from office.

The lawyer earlier attended the launching ceremony for the pro-Duterte group, Citizen National Guard, which labeled political opposition as enemies of the state.

Acosta's office, which has been assisting the families of all three slain teenagers, presented a new witness to the murder of Arnaiz, who was killed in a shootout after allegedly robbing a taxi driver.

The witness, identified as Joel Cruz, works at the funeral home that retrieved Arnaiz's body from the crime scene.

"Iyong kanyang testimony ay nagja-jibe sa forensic analysis namin dun sa probable time of death nitong si Carl na more or less four hours na siyang patay," said Acosta.