Ian Chase

Ian Chase is a socialite and presumed mobster, as well as a murderer.

Batman: Arkham Origins
During a Halloween party at Wayne Manor, Ian Chase ended up causing a disturbance (presumably by harassing Clarissa Rodriguez, based on a comment made by Alfred), forcing Bruce Wayne to throw him out. Two months later, on Christmas, Chase, by that time a gang member to the Joker (who had taken over Black Mask's gang) went to Crime Alley and proceeded to murder both Rodriguez and her fiancée, Horace Riley, by shooting her in the heart, and shooting him in the lung, respectively, coincidentally at the same spot that Wayne's parents had been murdered during a mugging during Wayne's childhood. Although Chase managed to clean up the area by removing most of the bullet casings, he missed one inside of the grate. Batman, Bruce Wayne's alter ego, managed to uncover the murder and deduced Chase's role in their murder. Batman then tracked Chase down to the Industrial District, where Chase alongside other mobsters were discussing his role in the murder (dialogue suggests that he would have been the number one suspect in Riley and Rodriguez's murders, but could not be convicted without proof). Batman then ended up attacking Chase and nearly killing him due to his petty reason for committing the murders before Alfred calmed him down.