Most of the victims of the November 2014 massacre lived here, in the Terra Firme favela, one of the poorest and most violent areas in the state of Para in Brazil. (Paulo Santos/REUTERS)

The corner where 16-year-old ­Eduardo Chaves was killed is just a few hundreds yards from a center that is a police station and a community center in this ­bustling slum. But no police intervened on Nov. 4 when he was executed by a convoy of masked men on motorbikes and in cars. He was one of 10 boys and young men gunned down that night.

Raul, a close relative, tried to save Eduardo when the killers accosted him. “I ran there to help him,’’ said Raul, who declined to give his real name. He was threatened with a shot over his head. A bystander bundled him away. He heard but did not see the shots that left Eduardo dead in a pool of blood. Raul said he felt “desperation, crying, sadness.”

A damning inquiry released Jan. 30 by the state assembly of Para — of which Belem, or Bethlehem, is the capital — said police colluded in a massacre that was announced beforehand. Its ramifications still reverberate through this Amazon city of 1.4­ million, where searching questions are being asked about Brazil’s epidemic violence — 56,000 people were killed in 2012 — and the role its underpaid police play on both sides of the front line.

The massacre was sparked by the killing two hours earlier of Antônio Figueiredo, a corporal in Brazil’s military street police, who was on extended medical leave, being forcibly retired and facing two homicide inquiries. Corporal Pet, or Pety, as Figueiredo was known, ran a vicious criminal gang, called a militia, from the adjacent favela of Guama that included military police officers.

His death incensed fellow officers, who took to social networks. “Friends, our little brother Pety, Corporal Figueiredo, was just murdered in Guama. I am going, I hope to count on the maximum of friends, let’s give the response,” Sgt. Rossicley Silva, a former colleague of Figueiredo in a SWAT unit and president of an association of noncommissioned police officers, wrote on Facebook. Silva told The Washington Post that his post had been misinterpreted and declined to comment further.

As warnings of the impending massacre pinged around Terra Firme on the cellphone chat service WhatsApp, Eduardo and his girlfriend went to collect her baby daughter from her nearby apartment. She was spared. He was not.

“This militia action in the neighborhood of Terra Firme happened with the total complacency, protection and guarantee . . . of the military police of the area,” said Para state legislator Carlos Bordalo, who led the inquiry. “The police cars provided logistical support­.­ . . . The police cars stopped the wounded from leaving to receive help outside.”

Relying on previous investigations and testimony from witnesses and police officers, the report concluded that at least five militias were operating in Para and had been behind massacres dating to 1994 in which police officers were involved and, in some cases, jailed.

It reads like a tropical James Ellroy novel. Militias offered private security services to local businesses, including contract killings and the execution of known criminals, and in Guama they also aimed to control the drug trade.

The police are conducting their own investigation. Gen. Jeannot Jansen, public security secretary for the Para state government, said Figueiredo was a good cop gone bad. “His service record was excellent until a certain time. From a certain moment, he got involved with people who presumably were part of criminality,” Jansen said.

Jansen said he was unable to confirm the existence of militias.

“Indications exist. That’s why there is this investigation,” he said. “Are there some indications that permit us to suppose that there was participation of police? Yes, there are.”

And if that can be proved, he said, “they will be punished.”

Some in Belem considered Figueiredo a sort of Wild West lawman who did the unpalatable so society could be safer. On a recent morning, two bare-chested men sat on the street in Guama where Figueiredo had lived, around the corner from the motorbike taxi point where he was gunned down.

“I liked him a lot,” said one, speaking on the condition of anonymity. He pointed to a security camera positioned high on a utility pole. “He put this camera here,” he said. “There was less crime. They respected him. Bandits did nothing.”

Others celebrated by setting off fireworks when Figueiredo was killed. “This Pet was known as an extremely violent person,” said a close female relative of Bruno Gemaque, 20, another victim of the massacre, also speaking on the condition of anonymity. “If he got it into his head that someone was a bandit, he would shoot and kill.”

Gemaque was killed in front of his girlfriend. He was giving her a ride home from school on his bicycle when the death squad apprehended them. “I couldn’t cry from so much anguish,” the relative said. “He was a very happy person.”

The phrase “a good bandit is a dead bandit” is used frequently in Brazil to justify police killings. Yet according to a confidential police report seen by The Post, only one of the victims was involved in crime. Relatives of four of the men proclaimed their innocence.

“He had no enemies,” said a close female relative of Márcio Rodrigues, 22, who was shot in the back as the killing spree neared its end. A close relative of victim Allersonvaldo Carvalho Mendes, 37, said he had learning disabilities and consequently did not heed warnings to get off the street.

Luiz Passinho, a military police soldier, said many off-duty officers do private security work similar to what Figueiredo’s militia offered. “It is illegal but is tolerated because it inhibits salary demands,” he said.

Unhappy about low pay and poor working conditions, Passinho joined a 2014 strike and is one of 41 officers facing internal charges. “What feeds the militia is exactly this dissatisfaction,” he said. “They look for that officer who needs income . . . that is feeling insecure, that officer that is revolted because of the death of a comrade.”

Until November, the word “militia” was barely used in Para, said Eliana Fonseca, ombudsman for the state security system.

The killings terrified residents. For days afterward, many stayed home as the city was paralyzed by “a reaction of fear, of insecurity,” she said, “as if we were in a society where anything could be done.”

Fonseca said militias like Figueiredo’s continue operating and killing but with less intensity — and more notoriety. Everyone here now knows what the word “militia” means.

In Brazil, unrest is simmering over bus fares, Olympic golf and Nazi cops

Videos of police crimes spur Brazilians to confront a longtime problem