The Ivy League think tank where lawyers found classified materials linked to the Obama White House is a patronage mill for the Biden administration, raising suspicions among critics that its establishment attracted tens of millions in donations from anonymous Chinese donors.

The Department of Justice is currently probing how “a small number” of classified documents from President Biden’s years as vice president ended up at the Washington, DC, think tank that bears his name, the White House confirmed Monday. A second batch of papers were found at an additional location, it was reported Wednesday.

The University of Pennsylvania received more than $30 million from Chinese donors shortly after the Penn Biden Center for Diplomacy and Global Engagement, which functioned as an office for Joe Biden before he was elected president, was announced in 2017, according to public records.

“The Penn Biden Center is a dark money, revolving door nightmare where foreign competitors like China donated millions of dollars to the university so that they could have access to future high ranking officials,” said Tom Anderson, director of the Government Integrity Project at the Virginia-based National Legal and Policy Center.