MANILA - Senator Risa Hontiveros said three witnesses, two of whom are minors aged 13 and 16, in the Senate's protective custody are prepared to face the probe on Kian Delos Santos' killing in an executive session.

Speaking to ANC Monday, Hontiveros said despite fear and trauma, the witnesses saw what the police did to the 17-year-old during an anti-drug operation in Caloocan City last August 16.

"Kaya sila natatakot kasi nakita nila ang ginawa kay Kian," she said referring to how the cops dragged and killed the 11th grader, whom police claim is a drug runner who fought them with a gun.

The senator said it is highly likely that these witnesses will be able to identify the cops tagged in the killing. So far, three cops from the Caloocan City police have been identified in the slay.

They are PO3 Arnel Oares and PO1 Jeremias Pereda and Jerwin Cruz, who already faced the Senate probe last week but were not able to answer all the lawmakers' questions.

"The witnesses na nasa protective custody ng Senate ay takot at traumatized pero matapang pa rin. They have the courage beyond their fear na sabihin nila 'yung kanilang nalalaman," Hontiveros said.

Delos Santos was killed in a raid that was part of an alleged "one time, big time" police operation on August 16. Cops say Delos Santos was carrying a gun and had fired first but CCTV footage caught two police officers dragging Kian before the teen was killed.

Autopsy also showed that the teenager was likely down on the ground, kneeling, when he was shot in the back of the head. Delos Santos also tested negative for gunpowder nitrates.

Delos Santos was laid to rest Saturday, with the funeral procession turning into a protest as various groups joined the march to La Loma Cemetery to call for a stop in the drug war killings.

• Kian's funeral procession makes stop at police station
• Wala na ang joker': Family, friends bid goodbye to Kian

The senator said she hopes the Public Attorney's Office (PAO) will not just dismiss the statements of these witnesses.

She also slammed Justice Secretary Vitaliano Aguirre for saying the witnesses may have been brainwashed.

"Hindi pa nga natitimbang ni Secretary ang bigat at halaga ng testimonya ng witnesses," she said.

Hontiveros said the affidavit of the witnesses is already being finalized. Senator Panfilo Lacson, who heads the committee on the probe on Delos Santos' killing, has yet announce when the hearings will resume.