At least five police officers have been killed and dozens injured in a bomb attack as they gathered for their morning briefing in Colombia’s coastal city of Barranquilla. Authorities suspect the “act of barbarity” was perpetrated by one of the country’s numerous criminal gangs as a retaliation against a recent police crackdown, Reuters reports. One suspect has already been arrested, but authorities believe more people could be involved and have offered a reward of 50 million pesos (some $18,000) for any useful information about the perpetrators.