US immigration laws prohibit the issuance of nonimmigrant or immigrant visas to anyone who has been convicted of or admits to the essential elements of federal controlled substances crimes. Generally, an admission to a drug crime happens in court as part of a plea or, in Massachusetts, a “continued without a finding.”
However, USCIS interviews can be the site of “admissions” to federal controlled substances crimes. In a green card interview, for example, a USCIS officer can ask an applicant if s/he has ever used, possessed, distributed, sold, etc. marijuana or any other federal controlled substances.
Apparently, just that has been happening at recent green-card interviews in Seattle. USCIS officers use the attached sworn statement to