(a) In all cases the Board shall consider the reports of investigation in the light of the standard as set forth in § 1501.8 and shall determine whether such reports warrant a finding favorable to the individual or appear to call for further processing of the case with a view to a possible unfavorable determination.

(b) If the Board reaches a favorable conclusion in a case involving a question of loyalty, it shall make a determination that on all the evidence there is not a reasonable doubt as to the individual's loyalty.

(c) If the Board determines that the reports do not warrant a finding favorable to the individual, or the Board determines that the evidence is of such a nature that a hearing may be required before a final decision is made, the Board shall send by registered mail, or in such other manner as the Board in a particular case may decide, a written interrogatory to the individual. Such interrogatory shall state the nature of the evidence against him, setting forth with particularity the facts and circumstances involved, in as much detail as security conditions permit, in order to enable him to submit his answer, defense or explanation and to submit affidavits. It will also inform the applicant or employee, of his opportunity to reply to the interrogatory in writing, under oath or affirmation, within ten (10) calendar days of the date of receipt by him of the interrogatory or such longer time as the Board in specific cases may prescribe, and of his opportunity for a hearing on the issues before the Board or a panel of the Board, including his right to appear personally at such hearing, to be represented by counsel of a representative of his own choosing, to present evidence in his own behalf, and to cross-examine witnesses offered in support of the derogatory information.