(Reuters) – U.S. defense contractor Altegrity Inc has hired restructuring advisers as it contends with a debt burden of about $1.8 billion, the Wall Street Journal reported on Wednesday, citing people familiar with the matter. Altegrity is the holding company for U.S. Investigations Services (USIS), the nation’s largest private provider of federal government background checks that became the focus of congressional scrutiny last year after it was discovered USIS vetted Edward Snowden before he leaked documents about U.S. spying efforts. USIS was also responsible for vetting Aaron Alexis, the technology contractor who killed 12 people at the Washington Navy Yard in September.