As jury selection began yesterday in the corruption trial of veteran Chicago fixer Antoin “Tony” Rezko, there was an unexpected face in the courtroom audience: an unidentified staffer scoping out the scene for Democratic presidential hopeful Sen. Barack Obama.

As Newsweek reported this week, Obama is a long-time friend of Rezko’s. In 2005, Rezko and his wife were involved in a tangled property deal in which Rezko’s wife bought a vacant lot next to a historical house purchased by Obama and his wife; Obama later acknowledged that his real-estate dealings with Rezko were “boneheaded.”

There is no allegation that there was anything illegal about the house deal or Obama’s role in it. But federal prosecutors have indicated in court papers that it is at least possible that Obama’s name could surface in Rezko’s trial on complex corruption charges. Government documents say that an unnamed politician received a $10,000 campaign contribution through a straw donor from Rezko, and that the money originated with a dubious “finders fee” paid to the developer as part of an allegedly corrupt scheme to influence members of a state teachers’ pension fund board. Chicago media have reported that the politician who received the $10,000 was Obama; this was confirmed to NEWSWEEK by a source close to the Rezko investigation, who asked for anonymity when discussing non-public information. (There is no suggestion that Obama knew that the campaign contribution was tainted, and he has donated $160,000 in Rezko-related funds to charity.)

Bill Burton, an Obama campaign spokesman, confirmed that a campaign representative was indeed present in the courtroom for Rezko’s trial. “She went to the trial to gather information since we’ve gotten so many media inquiries,” Burton said in an e-mail to NEWSWEEK.