Authorities in Brazil are investigating a killing spree in the city of Campinas that saw at least a dozen people die – and if that killing spree was the work of off-duty police officers.  The weapons used in the murders reportedly were of the same caliber of those used by cops.

What is undisputed as that the first person to die late Sunday was an off-duty police officer, killed during a robbery attempt at a gas station in the area. 

But between late Sunday night and Monday afternoon, twelve more people were killed.  In one incident, the attackers stopped their car next to a group of people, asked children to be taken away, and opened fire on those men remaining.  Some of the victims died at the scenes, others died in hospital. 

“We’re not ruling out executions, revenge nor a fight between criminals,” police investigator Licurgo Nunes Costa told the newspaper Estado de S. Paulo.  “It’s a sequence of events in the same region and around the same time, and we have to consider the relationship between the occurrences.”

But if these were revenge killings, they brought another round of retaliation.  Dozens of young men in masked attacked the city’s bus terminal, torching at least three buses and a car, as well as vandalizing the building.