"The military has always been a good way to sell firearms," a gun-marketing researcher said.
Criminal violence in the region centers around the theft of fuel from a nearby oil refinery.
Brazilian police killed at least 13 suspected drug traffickers on Friday in a shootout in Rio de Janeiro.
Here's our afternoon round-up of the key stories from Europe today.
Witnesses and victims shared their stories as the shooting took place, before talk turned to false speculation on the shooter's identity
Wireless signals can penetrate bags to get the dimensions of dangerous metal objects, including weapons and batteries for bombs, as well as estimate the volume of liquids such as chemicals for explosives.
Shooting happened after Caribbean carnival.
The gunman, who was said to have been suffering from post-traumatic stress disorder, was also found dead, as well as his three female victims.
As the nation engages in yet another bout of introspection, journalists must also look inward.