without an administrative hearing, § 1553’s pre-deprivation procedures, coupled with its provision for judicial review, provide BCI with sufficient protection against the risk of erroneous deprivation. The opportunity to participate in the investigation of the DOE’s OIG and submit a written rebuttal is no substitute for the opportunity to test adverse evidence and cross examine witnesses during a hearing. “[T]he primary function of the investigator is not to make credibility determinations, but rather to determine simply whether reasonable cause exists to believe that the employee has been discharged for engaging in protected conduct.” Brock, 481 U.S. at 266, 107 S.Ct. 1740. Additionally, a written rebuttal does not permit the fact-finder to assess the credibility of a witness. See id. (<HOLDING>). Nor does this court’s review provide
holding that material for witnesses need not be produced to defendant where the witnesses were not called as government witnesses at trial holding that the postconviction court is the sole judge of the weight of the evidence and the credibility of witnesses holding the opportunity to cross examine witnesses predeprivation is unnecessary where the statute provided for a postdeprivation hearing appropriately reserving fjinal assessments of the credibility of supporting witnesses  to the administrative law judge holding trial court is sole and exclusive judge of witnesses credibility holding that it is function of trial court to judge witnesses credibility and to weigh conflicting evidence