MANILA (Updated) -- Carl Angelo Arnaiz, the former University of the Philippines student who was killed by police officers in Caloocan City on August 18, tested positive for gunpowder nitrates, the Philippine National Police (PNP) Crime Laboratory said Tuesday, September 5, during a Senate hearing on drug war deaths.

Senior Superintendent Ligaya Sim, PNP Crime Laboratory deputy director for administration, said that based on the paraffin examination, gunpowder nitrates were found in the hands of Arnaiz, indicating that the 19-year-old student fired a gun.

Arnaiz was killed after he allegedly fired at the police officers who tried to arrest him for allegedly robbing a taxi driver along C-3 road in Caloocan City.

According to the incident report, Police Officers 1 Jeffrey Perez and Ricky Arquilita of Caloocan City Police Community Precinct 2 said they had asked Tomas Bagcal, the taxi driver who acted as complainant, to identify the suspect after they searched the area.

Authorities claimed Arnaiz, who resisted arrest, fired at the police officers, prompting them to retaliate.

Police said they recovered shabu (methamphetamine hydrochloride), marijuana leaves and the taxi driver's wallet from Arnaiz's possession.

The teenager, who lives in Cainta, Rizal, was found by his parents in a funeral home in Caloocan City 10 days after he was killed.

His parents, however, said they could not believe Arnaiz could do what the taxi driver and the policemen are accusing him of.

Autopsy report of the Public Attorney's Office (PAO) showed Arnaiz sustained five gunshot wounds, handcuff marks, abrasions in his back and legs indicating that he was dragged, and swollen eyes.

PAO forensic consultant Dr. Erwin Erfe said the report of the police is "too far" from their findings of what really happened based on their forensic analysis.

Erfe said Arnaiz's killing was intentional as the trajectory of the bullets was to the victim's chest, targeting his vital organs. 

Five bullets entered the victim's body, three of which were found in his chest, said Erfe.

Erfe added that the victim was tortured before he was killed.

"Mukhang nakaluhod po siya nang siya ay unang binaril, dalawa hanggang tatlong beses. At nang nakahiga ay may dalawa pang putok, sa dibdib tumama iyon (It appeared that the victim was kneeling when he was shot two to three times. Two to three more shots were fired while the victim was lying down, hitting the chest) ," he said.

Arnaiz went missing for 10 days before his body was found at Exequiel Funeral Homes in Caloocan City last August 28.

In Malacañang, Presidential Spokesperson Ernesto Abella gave assurance that justice would be served for Arnaiz's death.

Abella said the police officers involved in Arnaiz's slay would face appropriate sanctions if results of the investigation will prove treacherous action on their part.

"We assure the public that there will be no whitewash," Abella said in a press conference.

"There will be a thorough and impartial investigation, and those who will be found responsible will be made accountable before our laws," he added.

Meanwhile, Justice Undersecretary Erickson Balmes confirmed Tuesday that the parents of Arnaiz have been placed under the Department of Justice's Witness Protection Program (WPP). 

Balmes said Arnaiz's parents, Carlito and Eva, will be provided provisional coverage of the WPP as ordered by Justice Secretary Vitaliano Aguirre II. 

The PNP Criminal Investigation and Detection Group and the PNP Internal Affairs Service are investigating the incident, which took place two days after the killing of Kian Loyd delos Santos in an anti-drug sweep, also in Caloocan City. (SunStar Philippines)