After classified materials were found at an old office of President Joe Biden’s, aides discovered a second batch of classified documents at a location that Biden was known to use after leaving office as vice president, ABC News has learned. Biden aides were responding to the November discovery of classified documents at the Washington, D.C., office of the University of Pennsylvania’s Penn Biden Center, which Biden used after his time as vice president. It is unclear whether the search by Biden aides to check for other potentially classified government documents has been completed yet.