[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/images/07/09/art.holder.gi.jpg caption="Holder, right, and Caroline Kennedy are heading up Obama's VP search."](CNN) - Barack Obama made a surprise stop Wednesday morning at the Washington, DC law firm of his top VP vetter, Eric Holder.
Campaign aides declined to say exactly why the presumptive Democratic presidential nominee made the unscheduled stop, including whether Obama was specifically meeting with Holder.
Holder, a former deputy attorney general during the Clinton administration, is currently an attorney at the law firm of Covington and Burling. He serves as a legal adviser to Obama, and was tapped by the campaign last month to help steer the Illinois senator's search for a running mate.
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David Axelrod, one of Obama's top political advisers, accompanied the presidential candidate into the office.
Obama and Axelrod were in the building for a little more than an hour.