The latest Creatures of Middle-earth feature on the Lord of the Rings Online website goes into detail on the background of the Bandits and Brigands within Eriador.
The wild lands of Eriador are home to men of questionable character, who dwell within the many caves and darkened glens throughout the forests and hills. Lawless rogues all, they roam in search of treasure among the ruins of Arnor, and occasionally waylay wanderers on the roads. While such attacks have been rare in years past, and usually only involved the stealing of a bite of food or a fat coin-purse, recently brigand raids on unwary travellers have dramatically increased.
To read more, head over to the Creatures of Middle-earth: Bandits and Brigands feature.