The head of the Pentagon's investigative office says he is resigning, effective in January.

Jon Rymer, who was confirmed by the Senate two years ago as the Pentagon's inspector general, said in a statement released Monday that he will return to the private sector.

He called his resignation a difficult decision. Among other work, the inspector general's office is probing allegations by intelligence analysts at the U.S. Central Command that senior military officers there manipulated conclusions of intelligence reports on the war against the Islamic State to exaggerate progress.

Before taking the Pentagon job in 2013, Rymer had served as inspector general at the Federal Deposit Insurance Corporation and at the Securities and Exchange Commission. He is an Army veteran.

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