The problem with fingerprints is that any of Jodi's "friends" would be expected to leave prints in her apartment. This is, in my speculation, someone very familiar with her schedule. They may have even stayed over - the reason Jodi was late that morning. A disagreement could have started with her on the rush to get out of the apartment and when she got down to the parking lot, her angry friend wrestled away into his car and took off. Of course this is my theory, opinion only, and I hadn't thought of a stay over friend til now. I always assumed before that he was waiting for her outside.