The homicide rates rose sharply in the city of Porto Alegre between the years 2011 and 2016. This situation was compared to the "Barbarian Age" by the local press. However, due to the actions conducted in the public security sector from 2017 onward, the homicide rate went down 19% in the municipality and maintained this reduction throughout 2018 and 2019. Thus, this article aims to present the actions that were taken to fight the high homicide rates in Porto Alegre, mostly by describing Operation Firm Hand (Operação Pulso Firme), which took place in July of 2017. With this in mind, the exploratory study used bibliographic and documental review techniques and took into account scientific articles and media publications from public agencies and from the local press. The article exposes the main actions that were implemented in order to modify the scenario, comparing them with other successful cases in Brazil and internationally, presenting the aspects that had to do with actions focused on repressing criminal factions, thus reducing homicide rates.