Where is the android in the quest "A Replicated Man" in Fallout 3 for Xbox 360?

I have talked to ZImmerman. I have talked to Dr. Preston and I got the recording from him. I found Pinkerton, but there is no option to talk to him about an android. People have told me that Harkson or who ever is the Android but how do I solve this quest. Where do I go next. I want to convince the Android he is an ANdroid then tell Zimmerman I found him so that I get money, and the pistol. Then I will just kill Zimmermen. BUT WHAT DO I DO NEXT???