Special counsel Robert Mueller and the FBI investigated Attorney General Jeff Sessions last year for misleading lawmakers about his contacts with Russians before eventually closing that part of the case, according to three people with knowledge of the matter.

The investigation, which examined statements Sessions made last year during his confirmation process to become attorney general, was authorized by former FBI Deputy Director Andrew McCabe, according to the people, who asked not to be identified discussing a sensitive matter. Sessions fired McCabe on March 16 for a lack of candor and misleading Justice Department officials in a separate matter.

The probe into Sessions shows the breadth of Mueller's investigation and offers a rare glimpse into an episode that the special counsel has decided to close without charges. The investigation into Sessions was first reported Wednesday by ABC News.