Clinton’s use of private email, held on a private server at her Chappaqua, New York, home, for government purposes has come up in various investigations, and the controversy over it has hung over her campaign for months.

The report by the department’s inspector general cited “longstanding, systemic weaknesses” with State Department records that predated Clinton’s tenure, but criticized her for using private email for government business and for failing to turn over records promptly, media reports said.

“At a minimum, Secretary Clinton should have surrendered all emails dealing with department business before leaving government service and, because she did not do so, she did not comply with the Department’s policies that were implemented in accordance with the Federal Records Act,” the report read.

The inspector general’s report, released to lawmakers on Wednesday, said Secretary of State John Kerry and predecessors Colin Powell, Condoleezza Rice and Madeleine Albright were interviewed in the investigation, said Politico, which first reported the report’s conclusions.

The report said Clinton and her deputies, including Cheryl Mills, Jake Sullivan and Huma Abedin, declined to be interviewed for the inspector general’s investigation, Politico said.

Clinton, who is campaigning to become the Democratic nominee in the Nov. 8 presidential election, has been criticized for her use of the private email address and server in handling government business while secretary of state from 2009-2013.

The Federal Bureau of Investigation is investigating whether any laws were broken as a result of the server kept in her home.