The inquiry, which began in September, appears to focus in part on settlements made by the network’s parent company, 21st Century Fox, and how they were paid and accounted for internally, two people with knowledge of the matter said.
A former public relations chief for Fox News has been subpoenaed and granted immunity from prosecution, one of the people said. The former executive, Brian Lewis, started at Fox News when it was founded in 1996 and was once considered one of the closest aides to Roger Ailes, the former chairman who was forced out last summer amid a sexual harassment scandal. He was fired in 2013 and left the network with a settlement.
Mark Kranz, the former chief financial officer for Fox News, also was subpoenaed and has immunity, according to two people with knowledge of the matter. Mr. Kranz, who oversaw the network’s finances when it paid millions of dollars in settlements, was appointed to his position by Mr. Ailes in 2004, and resigned last year, a week after Mr. Ailes had done so.