He is a confirmed member of the Aryans for Justice. He is known to be the assistant to Erik Strauss, leader of the Aryans for Justice. He decorates his apartment with a Nazi flag bearing the Swastika symbol on it. He has harassed Yo Money. His girlfriend is Wendy James.
On Tuesday, detective John Carey came to Walker's apartment to question him about Yo Money, and probably to find out whether Walker was somehow involved with the murders of officers Robert Hickman and Rene Garcia. However, Walker escaped from the apartment while Carey turned off the radio. Wendy James appeared and attacked Carey with a knife, but he overcame her.
Walker tried to kill Carey at the City Hall on Wednesday, perhaps as a retribution for arresting his girlfriend. Carey overcame and arrested him. It is unknown what happened to Walker and Wendy James afterwards.
Walker and his girlfriend had nothing to do with the serial murders. Their role in the game is not more than a subplot, which resolved with Walker's arrest, for they are no longer mentioned in the game.
Dennis Walker is known for decorating his apartment with Nazi symbols on the wall.
Dennis Walker is known for using profanity at John Carey involving the use of the word "Fuck" especially if the player clicks the hand icon on his personal things in his apartment or shows him the items from your inventory.
"Yeah, come on in."
"I can't hear you!"
"What did you say?"
"It's from the Fatherlands, it's my fucking favorite!"
"Go ahead! Turn it down!"