The FBI was conducting a planned search Wednesday of President Joe Biden’s Rehoboth Beach, Delaware home as part of its investigation into the potential mishandling of classified documents, the president’s personal lawyer said.

The search follows a 13-hour, top-to-bottom review of his Wilmington, Delaware home on Jan. 20, when agents located additional documents with classified markings and also took possession of some of his handwritten notes.

The president has been voluntarily allowing the Justice Department into his residences as part of their probe that came about when his attorneys uncovered classified documents Nov. 2 while closing up an office at the Penn Biden Center, a think tank affiliated with the Ivy League school. Documents were also found at his Wilmington home by his personal lawyers, who initiated a search after the Penn Biden center documents were discovered.

“Under DOJ’s standard procedures, in the interests of operational security and integrity, it sought to do this work without advance public notice, and we agreed to cooperate,” said the statement from Biden’s lawyer, Bob Bauer. “The search today is a further step in a thorough and timely DOJ process we will continue to fully support and facilitate. We will have further information at the conclusion of today’s search.”

An FBI spokeswoman referred comment to the Justice Department. A spokesman there did not immediately return a message seeking comment.