Philippine police have told a Senate inquiry that a high school student they killed in an anti-drug raid last week had been involved in narcotics - but they only learned of this after they shot him dead.

His death has caused public outrage in the Philippines, with critics accusing President Rodrigo Duterte of turning a blind eye to police abuses.

Duterte says his crackdown on drugs will not stop - but he has told the police to only kill if necessary.

Al Jazeera's Jamela Alindogan reports from Manila.