Justice Department officials decided against an investigation into the Clinton Foundation after the FBI requested the agency open a case into allegations of corruption stemming from Hillary Clinton's tenure as secretary of state.

But the Justice Department's public integrity unit declined to pursue the probe given what it characterized as insufficient evidence, according to a CNN report Wednesday.

The State Department's seemingly preferrential treatment of foundation donors under Clinton's leadership has raised questions about whether she and her aides ignored conflicts of interest in order to help the charity's most generous donors. Emails made public this week have deepened suspicions that donors were afforded access and favors that other outsiders could not get from the agency.

FBI Director James Comey declined to comment last month on whether the FBI's reported investigation of the Clinton Foundation had concluded with a separate probe into Clinton's emails. For months, reports had hinted at a widening FBI inquiry related to the philanthropy's foreign activities.

The Justice Department did not immediately return a request for comment.