A rights watchdog in the Philippines will investigate President Rodrigo Duterte’s claims that he killed criminals while serving as mayor of the city of Davao, the BBC reported on Wednesday. The Philippines Commission on Human Rights will also probe reports which claim that “death squads” killed several hundred people in the city.

The Commission’s head Chito Gascon said that while Duterte was immune from prosecution while serving as president, it was important to “have a record and documentation [of events]” for the purpose of preserving any available evidence. A previous investigation into the killings in Davao in 2012 had not found any evidence against Duterte even though the Commission had recommended charges against him “under the doctrine of command responsibility”, Gascon said.

On December 12, the president reportedly told businessmen that he murdered suspects to “show the guys [the police] that if I can do it, why can’t you?”. “I was really looking for a confrontation so I could kill,” he said. Earlier in 2015, he had said that he had killed at least three men suspected of kidnapping and rape in Davao.

On Tuesday, the United Nations High Commissioner for Human Rights Zeid Ra’ad al-Hussein had said the Philippines should investigate Duterte’s claims. The UN official had said the killings would “clearly constitute murder”. “It should be unthinkable for any functioning judicial system not to launch investigative and judicial proceedings when someone has openly admitted being a killer,” he said.