Edgar Matobato, who claims he used to be a hitman for President Duterte, is to file a case at the International Criminal Court (ICC) accusing him of crimes against humanity.
Matobato maintains he was a foot soldier in the so-called Davao Death Squad and killed hundreds of people under the orders of the president when he was mayor of the city.
His testimony to the senate was initially denied by retired policeman Arthur Lascañas, who Matobato named as leader of the death squad. However, in a sensational U-turn, Lasacañas revoked his denial, admitting his role in the killings.
He also described how he had killed two of his brothers on Mr Duterte’s orders and firebombed a number of mosques.
Last week, senators said they found no proof of the two men’s testimony, and closed a hearing about the allegations. The president’s allies dismissed their testimonies as pure fabrication.
In a television interview, Matobato’s lawyer Jude Sabio said he would now file a case with the court in The Hague within weeks.
“Murder is a serious crime,” he said. “If it is committed as part of a widespread and systematic attack directed against the civilian population, it constitutes a crime against humanity.”
Duterte’s chief lawyer, Salvador Panelo, says the president is not threatened by any possible international court case. “The extrajudicial killings here are being done by the members of the drug syndicate themselves,” Panelo told news channel ANC. “The president is not behind it, and neither are the police.”
In a report last month, Amnesty International said the drug killings appeared to be “systematic, planned and organised” and could constitute crimes against humanity a conclusion shared by a report conducted by New York based Human Rights Watch.
Asked on Monday about the prospect of going to jail, the president said he gave clear instructions to police to kill if their lives were in danger, and reiterated that he took full responsibility for the crackdown.
“I will do what I say in public and I am ready to face the consequences,” he told a news conference. “If I go to prison, so be it.”