; (iii) there are serious reasons to believe that the alien committed a serious nonpolitical crime outside the United States before the alien arrived in the United States; or (iv) there are reasonable grounds to believe that the alien is a danger to the national security of the United States. (3) Determinations (A) Particularly serious crime For purposes of paragraph (2)(B)(ii), an alien who has been convicted of an aggravated felony or felonies for which the alien has been sentenced to an aggregate term of imprisonment of not less than 5 years shall be considered to have committed a particularly serious crime. Notwithstanding the previous sentence, the Secretary of Homeland Security may determine that an alien sentenced to an aggregate term of imprisonment of less than 5 years has been convicted of a particularly serious crime. (B) Danger to national security For purposes of paragraph (2)(B)(iv), an alien who is described in section 237(a)(4)(B) of the Immigration and Nationality Act ( 8 U.S.C. 1227(a)(4)(B) ) shall be considered to be an alien with respect to whom there are reasonable grounds for regarding as a danger to the national security of the United States. (4) Referral to asylum officer (A) Referral If an alien expresses to an immigration officer a fear that such alien’s life or freedom would be threatened in the country to which such alien will be expelled or that the alien would be in danger of being subjected to torture in such country, the immigration officer shall refer the alien for an interview by an asylum officer employed in the Refugee, Asylum and International Operations Directorate of U.S. Citizenship and Immigration Services for a determination pursuant to paragraphs (1) and (2). (B) Burden of proof