On my current run, I decided to try betraying abrams in junkyard, by telling the guards about his spawn while I had it on me. Kareem says that abrams will come for me someday to get his money back. I'm lvl 22 now and Ive walked around a bunch and so far nothing. If its not already in the game, I think he should be a random encounter somewhere with a group of oculites/mercenaries to get his money back or kill you. Probably hanging around somewhere in stealth.