MANILA – President Rodrigo Duterte on Wednesday said he prefers "independent agencies" to investigate his son, Davao City Vice Mayor Paolo Duterte, and son-in-law Manases Carpio over corruption and illegal drug smuggling allegations.

“I leave it to the independent agencies --- there’s the (Commission on Human Rights), which is making all the noise, and they have the (National Bureau of Investigation),” Duterte told reporters in a news conference in Davao City upon his arrival from Japan.

Duterte was reacting to a statement from his fierce political enemy, Senator Leila de Lima, that the President should “go after the real drug lords” including those who “are living right inside his own household,” in an apparent reference to the younger Duterte and his son-in-law who are accused by Senator Antonio Trillanes IV of being involved in the smuggling of P6.4 billion worth of shabu into the country.

“Who would believe me if I investigate my son and my son-in-law?” Duterte asked.

“Ikaw, can you investigate your mother or father?”

"If they are really guilty, then so be it. Di ba sinabi ko na sa inyo noong mayor ako? Anong order ko sa pulis? 'Barilin ninyo maski anak ko.' At that statement remains. Barilin mo," he added. "Pag naggamit ng droga o nakahawak ng droga, barilin mo. Extrajudicial killing, if you want. And I can understand."

"Wala akong ano… ipusta ko. When I said I --- I cast my future in my Presidency, hindi ako magpa-corny," Duterte said. "Kita mo mga Cabinet members, kaibigan ko lahat, sinipa ko. The last was the undersecretary of budget. He was around when I was campaigning. But the first one, the first Cabinet, was also the head of my campaign. Wala --- wala tayong magawa eh."

"So, kung makulong sila, eh 'di ipakulong mo. 'Yan, ganyan lang ang buhay. Walang pakornihan. Do not --- do not be so anxious or say sorry for asking the question," he said.

De Lima issued the statement aimed at Duterte after a certain Ricky Serenio, a supposed bagman of the Berya drug group, claimed in an affidavit that Senator Franklin Drilon and former Interior Secretary Mar Roxas were protectors of slain alleged drug lord Melvin Odicta Sr.

Odicta reportedly once controlled the illegal drug trade in Iloilo, where Drilon hails from. Both Drilon and Roxas have denied Serenio’s allegations.

Justice Secretary Vitaliano Aguirre earlier said that a preliminary investigation could be conducted since Serenio's affidavit may serve as a complaint.

The once-powerful Liberal Party, where De Lima, Drilon and Roxas belong, said Serenio’s surfacing shows the administration seems bent on "going all-out to demonize" their party and "divert attention" from pressing issues.