With its case against Standard & Poor’s Ratings Services nearing the finish, the Justice Department has turned its attention to another credit-rating firm under fire for issuing rosy grades on mortgage deals in the buildup to the financial crisis. Justice Department officials in recent months have quietly met with multiple former executives of Moody’s Investors Service to discuss ratings of complex securities before the crisis, according to people familiar with the situation. The Justice Department lawyers probing Moody’s are still in the early stages of their investigation, according to people familiar with the matter. It isn’t yet clear whether it...