An Afghan man who has been detained for nearly four months, despite being charged with no crime, will remain behind bars indefinitely after his asylum case was delayed once again last week.

Though the man has lived in the United States for more than four years and been repeatedly vetted by federal authorities, a Department of Homeland Security attorney announced in court that the government has not finished his background check and could not estimate when it would. Investigators have now asserted he poses a “potential threat” to national security.