Using GTA 5 as a venue of publicity isn't exactly new — it being used by an official law enforcement agency as a means of online publicity is novel. You know your local police force is pretty fly when they're replicating a high-speed chase inside Rockstar's hit open-world crime game.
The Polícia Segurança Pública, which is the national law enforcement agency of Portugal recently shared a video on their official Facebook page wherein a player in GTA 5 engages in some good old police work.
Oh, and this isn't just some agency's misguided attempt at capitalizing on something that's popular without actually knowing anything about it. This isn't a poorly edited video thrown together by the only officer in the station who once briefly held a controller in their hands.

What we're looking at here is an expertly put together video from a modded version of GTA 5 running not only a Portuguese Police Cruiser skin mod, but LSPDFR, which happens to be the biggest and most detailed mod developed for the game.
LSPDFR is something of a total conversion mod which turns the massive, vibrant world of GTA 5 into a police simulator. Players take on the role of a law enforcement officer, tasked with patrolling the city and responding to various emergencies.