Brazilian authorities were frantically searching for 126 violent convicts Wednesday, days after they escaped from a maximum-security prison in the northern city of Manaus during a riot in which 56 inmates were killed.
The 17 hours of violence broke out Sunday between two gangs competing for control of the cocaine trade through the Amazon. It turned into a massacre on a scale seldom seen. Many of the dead were decapitated or cut into quarters by fellow inmates and thrown over prison walls.
The Family of the North gang, which operates from prisons in Manaus, was responsible for most of the deaths, using machetes to slaughter rivals from the Sao Paulo-based First Capital Command gang, according to Sergio Fontes, the top security official in Amazonas state, where the Anisio Jobim prison complex is located.
Investigators said they discovered a network of tunnels under the prison floors that they believe was employed during the massacre and suggested that the killings were premeditated. In the days before the uprising, prison guards had come to believe that drug trafficking groups were smuggling in firearms, some of which were collected by police after the violence subsided.
Authorities have released little information about the hunt for inmates who escaped, other than to say that 184 had escaped and that 58 had been caught. The state Secretariat of Public Safety published photos of 90 escapees.
Most of the inmates at the prison had been convicted of murder, rape or violent gang activity.
Remains were still being identified, suggesting that it is still unclear who escaped and who died. At the morgue in Manaus, families were lined up in the scorching sun waiting for the bodies of their relatives to be released.
Suspects in the killings were being moved to high-security federal prisons while they await prosecution.
Fearing more violence elsewhere, state authorities transferred 223 inmates from other prisons to an abandoned jail in Manaus to protect them from gang violence. Other states are now on high alert for signs of brewing violence or planned escapes.
Riots in Brazil's prisons are common, but the massacre in Manaus is among the bloodiest in decades.
In 1992, police seeking to end gang violence at Sao Paulo's Carandiru prison stormed the facility, leaving 111 inmates dead. An appeals court recently drew scorn from human rights groups for voiding the conviction of 73 officers who had participated.
More riots occurred at various prisons across the country in 2002, 2010, 2011, 2014 and 2016, often attributed to overcrowding. The First Capital Command gang was protesting poor prison conditions when it took to the streets of Sao Paulo in 2006 and killed 40 police officers and penitentiary employees.
An estimated 656,000 people are incarcerated in Brazil's state prisons, which were designed for fewer than 400,000. The government has repeatedly promised to ease crowding but not managed to do so.
With roughly 3,000 people sent to prison every month, the inmate population has increased by more than 160% since 2000. Before Sunday's riot, the Manaus prison housed more than three times its capacity.
Camila Nunes Dias, a sociology professor who specializes in prison violence, organized crime and public safety, said she was not surprised by the violence there.
"The conditions are terrible, degrading, inhumane and favor the growth of violence and the organization of crime," she said.
Brazilian prisons are often managed by prisoners, which controls costs but leaves open the risk of conflict as various factions struggle for control, she said. Building more prisons without making other changes would not quell the violence, she said.
"The authorities want to give the impression that all this was a surprise and that they did not know that it could happen," she said. "In fact, these tragedies are more than advertised and the conditions for them to happen are there, always present."
The country's justice minister, Alexandre Moraes, told reporters Wednesday that Amazonas state authorities knew of the possibility of a riot and prison break sometime between Christmas and New Year and had reinforced security at the Manaus complex.
They had not relayed those concerns to the federal government, he said.
President Michel Temer announced that he would meet Thursday with the attorney general and ministers of justice, defense, institutional security and transparency to discuss the penal system crisis.
At the Vatican, Pope Francis prayed for the victims in his Wednesday Mass, saying he was "pained and concerned" and calling for prisons to be "places of reeducation" and "places for reinsertion" into society when sentences are completed.