MANILA - President Rodrigo Duterte on Tuesday vowed justice for victims of a massacre in San Jose del Monte, Bulacan, even as he promised to remain harsh in his war on drugs- illegal substance often linked to heinous crimes.

“There will be justice. Paano? I don’t know how, “ Duterte told reporters after visiting the wake for Estrella Carlos, her three children aged 11, 5 and 1, and her mother-in-law Auring Carlos.

Pres. Rodrigo Duterte visits wake of Bulacan massacre victims. #MEWCY #ANCRecap pic.twitter.com/l0RV4x6jv3

— ABS-CBN News Channel (@ANCALERTS) July 4, 2017

Duterte said he received information that one of the “persons of interest” in the killings has been found dead.

“Basta sabi nila patay na 'yung isa. 'Pagka ganoon, there will be many more to come,” he said.

(They said one of them is dead. If that’s the case, there will be many more to come.)

The President did not not mention the name of the man slain, but police earlier reported finding the possible remains of Ronald Pacinos alias “Inggo,” one of the two alleged cohorts of the arrested suspect, construction worker Carmelino Ibañez.

Ibañez earlier tagged Pacinos and an alias “Tony” in the killings. Tony was arrested on Friday. He said they raped Estrella and her mother-in-law while under the influence of drugs and alcohol.

• Read: 'Trip-trip lang': Man admits raping 2 Bulacan massacre victims while high on drugs

While Ibañez admitted that he had used drugs before carrying out the crime, his drug test yielded a negative result.

• Read: Duterte, nagpupuyos sa mga nasa likod ng 'Bulacan massacre'

Speaking to reporters, Duterte again said his government would continue to be harsh against those involved in the illegal drug trade.

“I don’t give a shit about human rights. Wala akong pakialam sa kanila basta ako may trabaho ako. My job is to see to preserve and defend the filipino nation,” he said.

Government has called the war on drugs a success, citing the high number of arrests, seizures of illegal drugs, and dismantling of drug laboratories since its launch.

This despite international criticism over alleged extra-judicial killings and other human rights abuses under the anti-drug war. The administration has many times denied sanctioning extra-legal means to go after drug suspects.