Jennelyn Olaires hugs the dead body of her partner Michael Siaron, a pedicab driver, at LRT EDSA Rotonda in Pasay City, Metro Manila in 2016. Siaron was killed by unidentified gunmen. Basilio Sepe, ABS-CBN News/file 

MANILA -- Senate Minority Leader and Senate Committee on Justice chairman Senator Aquilino “Koko” Pimentel III on Thursday said around four victims are expected to testify at the start of their probe on former President Rodrigo Duterte's drug war.

He also said in a text message that Senator Ronald dela Rosa is welcome to join the hearings to share his knowledge about the subject matter.

Bato says he has 'no idea' about alleged reward system for cops in drug war

Pimentel believes around 3 hearings are enough to cover the drug war. He is eyeing Senator Joel Villanueva as a possible Subcommittee chairperson.

The former will preside the hearing since Senate Blue Ribbon Committee chairman Senator Pia Cayetano is currently on a summit for the Commission on Energy.

The decision for Senate to initiate its own probe on war on drugs was formed after several revelations and allegations floated during the House Quad Committee hearings, wherein retired police colonel Royina Garma claimed there was a cash reward system for every drug suspect killed.

Cayetano, Pimentel to lead Senate probe on Duterte's drug war

Pimentel, a former member of the Duterte-led PDP-Laban party, is now leading another faction of the party that no longer includes Duterte, dela Rosa, or Senator Bong Go who are all being mentioned in recent House hearings on drug war.

Cayetano won a Senate seat in 2019 after running under the Hugpong ng Pagbabago administration coalition. Dela Rosa and Go were also part of the coalition.