Bangkok: Philippine police claimed it was an encounter with a drug suspect in a dark alley.
But CCTV footage shows that 17-year-old Kian Loyd delos Santos was dragged past a basketball court into a dead-end screaming, "Please can I go home. I have school tomorrow".
Witnesses say delos Santos was handed a gun and ordered to run.
His dead body was found in a fetal position, wearing a blue shirt and boxer shorts, a gun in his left hand.
The execution was one of 81 deaths in the bloodiest five days yet of president Rodrigo Duterte's so-called war on drugs.
Children as young as three have become what Mr Duterte describes as "collateral damage" in the crackdown where hooded hit-men and police have killed thousands of Filipinos, most of them in crime-prone urban slums.
But the killing of delos Santos has resonated across the Philippines in a way that none other has done since the bloodshed began when Mr Duterte took office in June last year.
Church leaders have led the outcry, decreeing that church bells will be rung for 15 minutes every night for three months to raise alarm over the escalating killings.
And Mr Duterte's powerful allies in the Philippine senate have broken ranks and signed a resolution condemning "the recent spate of abuses by police resulting in excessive and unnecessary deaths in the conduct of the campaign against drugs".
The senate majority bloc also agreed to set up a new inquiry into the killings, including that of delos Santos in Caloocan City in Manila metropolis last Wednesday night.
Philippine vice president Leni Robredo explained the backlash against Mr Duterte, saying "you know, this is something personal to me because he (delos Santos) was the same age as my youngest daughter. That's why when these things happen, you will think that if it happened to him, it could also happen to our children".
"This is saddening. Now Kian gives it a human face. How many Kians have we had? How many more Kians will follow? That's why when this happens, I think it is our obligation to express our condemnation," she said.
Unlike other teenagers in his neighbourhood, delos Santos never ran around playing on the streets and his family and friends are shocked at insinuations by police that he could have been involved in drugs, family members and friends told the Philippine media.
Every day he would man his family's small convenience store from 5.30am until noon before going off to high school, where teachers and friends said he never once got into trouble, Rappler online news reported.
Saldy delos Santos told reporters that if his son had any spare time he would watch funny videos on YouTube and sing rap songs.
He shared a bed with his three siblings.
A few hours before the killing, Kian's father, Saldy sent his son a message telling him to sleep early and be careful around the streets.
"You know how it is in our street, it can be dangerous," the father said in his final advice to his son, Rappler on-line news reported.
True to form, Mr Duterte's response to the killing spree was to express his wish more people would be killed and to lash out at human rights defenders, telling police to shoot them as well if they get in the way.
Police initially said they would conduct an investigation into delos Santos' supposed drug dealings.
But as anger grew when it became clear he was executed three police were stood down, pending a wider probe.
Archbishop Socrates Villegas, who heads an influential bloc of Catholic bishops, said the sound of the bells in his northern Archdiocese "is the voice of God that we hope will wake-up numb and blind consciences. You shall not kill! That is a sin. That is against the law. That is what the bell is saying."
"The country is a chaos. The officer who kills is rewarded and the slain get the blame???the corpses could no longer defend themselves from accusations that they fought back," he said.
Manila Cardinal Luis Antonio Tagle called for an end to the "waste of human lives."
"We knock on the consciences of those who kill even the helpless, especially those who cover their faces with bonnets and to stop wasting human lives," he said.
The comments are the strongest yet from the church which has been one of the few voices denouncing the deaths in the pre-dominantly Catholic country while Mr Duterte has enjoyed widespread popularity.
Now senators have also turned. For 14 months, the majority has strongly supported the president, but now they have made a joint public stand that will embarrass him. Among those backing the statement is Senate president Aquilino Pimentel, who said, "Of course it's getting alarming, not just because a young man was killed, but because there are people getting killed".
The inquiry will be conducted by the senate's committee on public order and dangerous drugs chaired by Senator Panfilo Lacson, a former national police chief.
But it is unlikely to deter Mr Duterte, a 72-year-old boastful and foul-mouthed former provincial mayor, from a bloody crusade that human rights groups say could amount to a crime against humanity.
When he took office last year he pledged to eradicate all drugs in society in six months.
But in recent speeches he has said he is unlikely to achieve the goal by the time he has to stand down as president in 2022.
Former congressman Walden Bello estimates that by then the death toll could reach 60,000, if the current rate of killing continues.
The toll is already the largest number of civilian deaths in south-east Asia since the Khmer Rouge genocide and Vietnam war in the 1970s.
Meanwhile, human rights groups have expressed outrage at Mr Duterte's instruction last week to police to "shoot those who are part of (drug activity). If they (members of human rights organisations) are obstructing justice, you shoot them."
Phelim Kine, deputy Asia director at Human Rights Watch, said the president's comments are "like painting a target on the backs of courageous people working to protect the rights and upholding the dignity of all Filipinos."
"Duterte should retract his reprehensible remarks immediately before there is more blood on his hands," he said.
With agencies
