India, Jan. 30 -- The Philippine National Police-Internal Affairs Service (PNP-IAS) has formally begun a pre-charge investigation into six police officers accused of robbery-extortion in Makati City.

IAS Inspector General Brigido Dulay said the investigation will be thorough and uncompromising.

"The Internal Affairs Service will leave no stone unturned in unmasking all those involved in this illegal activity," he said in a statement Friday.

"We will not tolerate criminal conduct in the police service, and those found liable will face the full force of the law."

A pre-charge investigation is a preliminary evaluation to determine probable cause.

The six officers, assigned to the Drug Enforcement Unit (DEU) of the Malate Police Station ...