MANILA (Reuters) – A Philippine lower court found three police officers guilty of murder on Thursday for the 2017 killing of a 17-year-old high school student, the first conviction in President Rodrigo Duterte’s war on drugs.

The three police officers were sentenced to up to 40 years in prison by a Caloocan regional trial court, in what is the first guilty verdict in an extrajudicial killing in the 29-month anti-narcotics campaign, according to human rights advocates.

They will not be eligible for parole, the court said.

The death of Kian Loyd delos Santos in August 2017 has stirred unprecedented public attention on what activists say are executions and systematic abuses by police backed steadfastly by Duterte.

“The conviction of the three police officers for murdering Kian de los Santos is a victory for justice but it is not enough. The killings must stop,” said Jose Manuel Diokno, chairman of the Free Legal Assistance Group (FLAG).

FLAG has questioned the legality of the drugs war before the Philippine Supreme Court.

Close to 5,000 people have died in the anti-drugs police operations and more than 2,500 others have been killed by unknown vigilante groups in what police said were drug-related incidents.

Human rights advocates said most of the victims who police said had resisted arrests were actually executed because there was a pattern on how they were killed. Police denied the allegations, saying they acted in self-defense.

Duterte’s government has repeatedly said there was no declared policy to kill drug users and pushers.

Delos Santos was found dead in an alley with a gun in his left hand. Police said they killed him in self defense, but his family dismissed that as a lie.

Security cameras showed the officers aggressively escorting a man matching delos Santos’ description in the direction of the spot where he was killed.

Two months after the delos Santos killing, Duterte ordered the police to stop its anti-drugs operations as the school boy’s murder sparked public outrage, but he reinstated police’s role in the drugs war in early December last year, saying the drug situation has worsened.