Matter of Davey, 26 I&N Dec. 37 (BIA Oct. 23, 2012) (The relevant question in a Joseph hearing is whether the DHS is substantially unlikely to prove a charge that would justify mandatory detention. Matter of Joseph, 22 I&N Dec. at 800. To prove a charge under section 237(a)(2)(B)(i), the DHS bears the burden of proving that the respondents conviction does not fall within the possession for personal use exception. See Matter of Moncada, 24 I&N Dec. 62, 67 n.5 (BIA 2007). It cannot meet that burden unless the record establishes that the respondent possessed marijuana for some reason other than personal use; an inconclusive record is not sufficient.).