FBI Deputy Director Andrew McCabe in the days leading up to his forced resignation Monday threatened to “torch” the FBI if he was expelled from his job without full retirement benefits, according to sources with direct knowledge of private conversations McCabe shared with agents. “He was unglued,” one FBI source said. “Someone should keep an eye on him.” But McCabe may also have been reacting, in part, to another growing problem beyond the corruption scandals enveloping McCabe’s leadership at the embattled FBI. An FBI insider with Intel inside the embattled Bureau who has vigilantly worked to uncover systemic corruption inside...