I'll give you a hint for where to find the true Corin-Rogue.
Corin Rouge is a wanted criminal that the player encounters multiple times in the game.
In the game
This article contains plot details about events that occur later in the game.
In the Grand Hall, the player can interact with a salesman to purchase an ultra rare Pokemon for 500 pokedollars. After the player purchases the Pokemon, it will be stolen by a street rat.
Inside a house in the Peridot Ward, the player will be able to find the street rat that stole the Pokemon. The street rat will return the Pokemon if you pay him another 500 pokedollars. However he reveals that the salesman and him were partners that rip money off trainers. After defeating both of them, the street rat tells the player that the ultra rare Pokemon has been stolen by a youngster.
In the slums, the player encounters the youngster that stole the Pokemon. After defeating the youngster, he reveals that some gang member has bought the Pokemon and the Pokemon isn't with him anymore.
In the North Obsidia Ward, a Magma gang member tells the player that he bought an ultra rare Pokemon from a kid but was stolen by an Aqua gang member. Later, an Aqua gang member challenges the player into a battle, quoting "I'll put you down just like I stomped out the one I stole that Pokemon from". After defeating the gang member he mentions that he has already sold the Pokemon in the 7th Street.
In the 7th Street, a salesman is willing to offer the player an ultra rare Pokemon he bought from a gang member for the price of 2 Blue Shards. After purchasing the Pokemon, Corin Rogue appears and steals the Pokemon away from the player.