The complaint was filed last May with the intelligence community’s inspector general, WSJ reported in its description of a November letter to Gabbard from Bakaj. It’s understood to also implicate another federal agency and to raise potential claims of executive privilege, suggesting possible White House involvement.

Members of the House and Senate intelligence panels first learned of the complaint in November, six months after it was filed, when a copy of Bakaj’s letter was shared with them, WSJ reports. Since then, Democratic staffers have tried unsuccessfully to learn more about it, congressional aides told the newspaper.

The complaint is so highly classified that Bakaj hasn’t been able to view it himself; a spokeswoman for Gabbard’s office confirmed that the complaint involved Gabbard but dismissed it as “baseless and politically motivated.”