A Pennsylvania detective is trying to figure out how an apparent prankster was able to fill out a 2008 voter registration card signed "Barack H. Obama." By the time Butler County elections officials processed the card, it went into the state's computerized database with the last name "Obana" - that is, with an `n' in place of the `m.' But a detective tells The Associated Press that whoever did it was clearly trying to register using President Barack Obama's name.