The Marauders were a mafia known in London, they bought police officers and were the reason the place was no longer so safe, they ran pubs, opened casinos, everything that went beyond the law, they had.

Sirius and James usually took care of the dirty work, they liked to get their hands dirty, Peter was more careful, more fearful, as Sirius said, Peter liked the part of making plans and solving internal problems, and Remus was basically the boss, he reviewed everything and he was the one who said what would be put into practice or not, Remus was more cunning and clever than anyone would have thought