Several years ago, Earth and Equestria have successfully made a connection with each other. After a portal was formed between Equestria and Earth, Princess Twilight Sparkle, the ruler of Equestria, has met up with the President of the United States, the country where the portal was formed on Earth, as well as several other world leaders, and agreed to have a partnership. Since then, humans and ponies have been free to travel to each other's worlds as they pleased, ponies and other creatures going to the human world, and humans going to the pony world, all for different purposes like residence, vacation, business, and education. But among these humans, there are some with less than favorable intentions.
With a portal between two worlds that's free to be accessed by anyone at any time, there are bound to be individuals or groups who'll use this newfound opportunity to commit nefarious acts. While the portal has only been open for a few years so the criminal activity around them isn't high yet, there seems to be a slow but steady rise of it as the years go by.
The rise truly took a height when a notorious crime family from Earth began expanding their business and influence into Equestria, becoming one of the first, or at least the first biggest mob activity between two worlds.
This is the rise and fall of the Silano crime family in Equestria.