MANILA - Embattled SPO3 Ricky Sta. Isabel, a suspect in the kidnap-slay of South Korean businessman Ick Joo Jee, attended Thursday the opening of a Senate inquiry into the crime that has triggered a new wave of intense scrutiny on President Rodrigo Duterte's war on drugs.

Also present at the probe were Philippine National Police chief, Director General Ronald "Bato" dela Rosa, and resource persons from the PNP, Anti-Kidnapping Group, and the National Bureau of Investigation.

Sta. Isabel and several cops from a special anti-drug unit allegedly abducted Jee from his home in Angeles, Pampanga last October 18 under the guise of a legitimate "Oplan Tokhang" raid.

The Korean was brought to Camp Crame and strangled to death before his remains were brought to a funeral home in Caloocan, the Justice Department confirmed last week.

The kidnappers demanded a ransom from the victim's wife and she initially paid P5 million, thinking he was still alive.

During the hearing, Dela Rosa reiterated Jee's killing indicates that there is a crime syndicate using legitimate police efforts to mask their nefarious activities.

"All indications point to an elaborate web of criminal activity by some police personnel operating under the cover of legitimate police operations," he said.

The case, he said, should "should serve as an eye opener, not only for the PNP but for the entire justice system that are in need of legislated reforms."

• 'Big syndicate' behind Korean's murder; suspect under threat: Bato

Police, in the heels of Jee's death, have come under intense scrutiny as the frontline troops in Duterte's efforts to eradicate illegal drugs in society, with human rights groups accusing them of mass extrajudicial killings.

Several groups have also accused Duterte of promoting a culture of impunity with his repeated promises to protect cops from prosecution if they are charged with murder for killing a drug suspect.

Duterte's efforts dismissed the accusation and vowed to deliver swift justice for the Korean.

• Palace apologizes to South Korea over Jee slay

Senator Panfilo Lacson, a former PNP chief, led the investigation as chair of the Senate committee on public order and dangerous drugs.

-- With Agence France-Presse