MANILA - Malacañang on Tuesday said there would be no whitewash in the investigation of the killing of 19-year-old Carl Angelo Arnaiz, whose death has been compared to the controversial shooting of 12th grader Kian Loyd Delos Santos.

“We assure the public there will be no whitewash and there will be a thorough and impartial investigation,” Presidential Spokesperson Ernesto Abella said in a news conference in Malacañang.

“Those found responsible will be made accountable before our laws.”

As public outrage has yet to ease in the wake Delos Santos' slay in an anti-drug operation on Aug. 16, the killing of Arnaiz in yet another questionable police operation drew suspicion of abuse against the police force.

Arnaiz was killed in an alleged shootout after the former University of the Philippines student purportedly robbed a taxi driver on Aug. 17, the same night he left their home in Cainta, Rizal.

A police spot report said marijuana leaves were recovered from the teenager.

The boy's family rejected the allegations, saying he only went out with a friend for midnight snacks.

Forensic experts from the Public Attorneys Office (PAO) found possible signs of torture on Arnaiz' body, including bruises and handcuff marks.

Bullet trajectory analysis meanwhile indicated that the teenager was already kneeling or sprawled on the ground when he was shot at least 5 times.

Such circumstances bore similarities to the death of Delos Santos, who was killed while already slumped on the ground. Witness statements and security footage indicate the boy was murdered.

• READ: PNP, PAO agree on autopsy: Kian already down when shot

Two neophyte cops tagged in Arnaiz' killing have been relieved from duty and placed under restrictive custody, said Metro Manila police Director Oscar Albayalde.

The National Capital Region Police Office (NCRPO) is set to review all Caloocan police operations amid allegations of abuse, said Albayalde.

PAO chief Persida Acosta said her office has secured the cooperation of a witness to Arnaiz's killing and has sought help from the National Bureau of Investigation to search for his 14-year-old companion on the night he went missing.

The string of killings of teenagers in anti-drug raids have put into question the legitimacy of police operations being carried out under President Rodrigo Duterte’s war on drugs.

Duterte, who has repeatedly promised to protect policemen who would be prosecuted for carrying out their job, recently toned down his rhetoric, saying “unlawful killing” is not allowed and that erring and abusive cops should not expect any support from him.

• READ: Duterte to cops: 'Unlawful killing' not allowed

Malacañang has repeatedy denied that it was behind extra-judicial killings in the drug war.