MANILA - President Rodrigo Duterte may have put himself and the justice system in trouble by reiterating his vow to pardon any police officer who would be convicted in the killing of drug suspects, a member of the academe said Thursday.

Duterte renewed Wednesday his promise of legal protection to cops at the helm of his war on drugs, just days after several policemen surrendered over the death of Albuerta, Leyte Mayor Rolanda Espinosa Sr., an alleged drug protector.

"I don't think that serves the purposes of law enforcement well. I think it erodes the criminal justice system. And that might not be good for the President himself," said Fr. Ranhilio Aquino, dean of the San Beda College Graduate School of Law.

Aquino explained that Duterte's statement may be taken as encouragement of a culture of impunity among the police -- an issue that has been raised by several international bodies, including the
International Criminal Court.

"I ask myself whether or not that sends a very dangerous signal to those who carry arms which others do not carry and who in the name of law, take it upon themselves to simply kill those they suspect as drug pushers," he told radio DZMM.

"Now that there is plenty talk about his liabilities under international convention, this certainly does not help him at all."

Insinuations that the police can set aside law in the performance of their duties will remove confidence in the justice system, Aquino added.

The dean noted that a president could only grant pardon if evidence surfaces in the favor of an accused after he was convicted by the Supreme Court.

"You usually do that with plenty of care, circumspection and you must present overriding value on why you are doing this because you are actually entering the threshold of the powers of another branch of government," he said.

Former justice undersecretary Ramon Esguerra meanwhile said promises of pardon for Espinosa's alleged killers may still be premature because they have not even been arraigned yet.

"The most I can say is premature. Hindi pa rin naman natin malaman baka i-acquit iyan e," Esguerra told radio DZMM.