The prosecutions key witness has concluded her testimony in the Tom Petters trial.  Attorneys for the Minnesota businessman accused of a massive Ponzi scheme are highlighting recordings made by Deanna Coleman in which company officers appear to wonder how much Petters knows about the scam.  Lawyers for Tom Petters questioned Coleman, the aide who ultimately blew the whistle on what prosecutors say was a $3.65 billion fraud, in her third day on the stand. Coleman wore a wire after going to the FBI in September 2008.  In one conversation, Petters Co. Inc. executive Bob White says to Coleman, "I can't tell for sure if Tom knows.'' Coleman responds, "Tom knows. He just doesn't want (to) think about it.''  Coleman goes on to say, "I think Tom believes that these are real deals half the time.'' White is heard answering, "I don't know for sure what Tom knows, you know, and he lives in his fantasy world once in a while.''  Petters' attorneys say he is innocent and didn't know what Coleman, White and others were doing behind his back. Both Coleman and White have already pleaded guilty in the case.