Former President Joe Biden is suing the Department of Justice in an effort to block the release of private conversations and audio recordings tied to special counsel Robert Hur‘s classified documents investigation.

Hur investigated Biden’s handling of classified documents and interviewed the former president about conversations with ghostwriter Mark Zwonitzer for his 2017 memoir, Promise Me, Dad: A Year of Hope, Hardship, and Purpose. The interviews, conducted between 2016 and 2017 at Biden’s home, were recorded as part of the book writing process.