The House quad committee has raised serious doubts about the Senate's planned parallel probe into the Duterte administration’s bloody drug war to be spearheaded by Senator Ronald "Bato" dela Rosa, who is being implicated in the investigation.

Panel chair Representative Ace Barbers explained that while it is within the rules of Congress, he expressed concern that it would affect the impartiality of the inquiry given Dela Rosa's prominent role as a key enforcer of the anti-drug campaign.

"I think there is no prohibition as far as conducting committee hearings. But the bigger question that should be ask, why would investigate yourself in your own committee?" Barbers said in an interview.

Santa Rosa Representative Dan Fernandez, a co-chair of the mega-panel, echoed Barbers, saying it would be a “clear case of conflict of interest.”

“Senator Bato should show delicadeza. For me it is highly inappropriate for him, the chief enforcer of the drug war, to lead a probe into the very operations he designed and implemented,” said Fernandez.

“As the architect of the war on drugs, Sen. Bato would be practically investigating himself. This undermines the integrity and objectivity of any findings that may result from this investigation,” he added.

To recall, Dela Rosa on Wednesday announced they will carry on the probe even if Congress is currently on a break and is “sure” that his ex-boss, former President Rodrigo Duterte, will face the Senate hearing over the other one in the House.

Former senator Leila de Lima, who was allegedly framed up by Dela Rosa on the illegal drug trade that led to her unjust six-year-long arrest, said it was "very funny" of De la Rosa to launch an investigation into the brutal war on drugs, in which he is highly involved.

"He is like an accused who is also the judge in his own trial. There is no other end to this if not another fraud on the people by Duterte and his tentacles in the Senate," she wrote in Filipino on X formerly Twitter.

Meanwhile, Barbers said they will instead back the proposal of Senator Risa Hontiveros to convene the Senate Committee of the Whole to probe the brutal anti-drug campaign of the previous administration.

"We are very pleased that both houses of Congress are of one mind in this. If it is true that there are 'allowances' given, Sen. Bato should explain why, who it went to, and where it came from," Barbers said.

Last week, Duterte's alleged trusted aide, retired police colonel Royina Garma, confirmed told the quad comm that the Duterte administration mimicked the so-called "Davao model," a system rewarding police for killing drug suspects as high as P1 million on a national scale.

According to Garma, an assembly was held in May 2016, a month before Duterte took office, to discuss the creation of a task force that would implement the nationwide killing.

She claimed that the monetary rewards for drug-related killings ranged from P20,000 to P1 million, depending on the prominence of the target.

Garma said a weekly report of fatalities was then being submitted to then Special Assistant to the President and now Senator Christopher "Bong" Go, who will hand the same to Duterte to request refunds for operation expenses.

Dela Rosa and Go, both long-time allies of the former president, denied Garma's allegations.

In 2016, Duterte admitted the existence of extrajudicial killings (EJK) but contended that it was not state-sponsored.

The government lodged more than 7,000 deaths under Duterte's notorious drug war.

Local and international human rights organizations, however, estimated that the death toll exceeded 30,000, affecting predominantly low-income families and communities.

The International Criminal Court (ICC) is keen to probe Duterte’s alleged EJK especially now that the family of the victims and the perpetrators are starting to come forward.

The Philippine government, however,  maintained that it will not submit to the ICC notwithstanding the findings of the quad committee.