In defense of his men, Philippine National Police (PNP) chief Director General Ronald "Bato" Dela Rosa again broke into tears.

A visibly upset Dela Rosa raised his voice and shed tears as he denied that the PNP had a policy to kill drug suspects at Tuesday's hearing at the Senate, which is investigating recent controversial deaths in police operations.

"Masakit 'yung magpapakamatay kami para sa inosenteng tao tapos sasabihin ninyo may polisiya kami sa pagpatay," Dela Rosa said under the questioning of Sen. Risa Hontiveros.

"I am with you in that quest for justice (for extra judicial killings), but sana 'yung hustisya din para sa mga pulis ko," he said.

Dela Rosa's emotional outburst was triggered after Hontiveros alleged that policemen seemed to be empowered by a culture of killing.

"May polisiya na nagdidikta sa kultura ng patayan na nangyayari sa ating bayan. There's a system to the killings. There's a method to the madness," Hontiveros said.

But Hontiveros clarified she was alluding to President Rodrigo Duterte's call for a bloody campaign against drug pushers, and not on Dela Rosa's performance as police chief.

"Mamatay man ako ngayon, walang sinabi si Presidente sa akin na pumatay kami ng pumatay. Paano ko dipensahan 'yung organisasyon ko kung yung utak niyo sarado na?" Dela Rosa said, citing how the PNP had been prejudged by certain lawmakers.

Dela Rosa is among resource persons invited to the Senate committee on public order and dangerous drugs' hearing into recent controversial killings, including the slay of 17-year-old Kian Loyd Delos Santos.

Police had said Delos Santos, an alleged drug courier, shot at pursuing officers during an anti-drug operation in Caloocan City on Aug. 16.

But security footage and witness statements indicate that the boy was executed. His family also denied he was involved in illegal drugs.