Former FBI agent Jennifer Coffindaffer has been closely following the case. When asked this question (interview with NewsDaddy Brian Entin), she emphatically stated the FBI does not know the location of BL.
under the circumstances, imaginatively, the fbi has a duty to protect members of the public from a suspect in a crime who is considered to be dangerous, if not armed and dangerous, even if the relevant evidence is not released to the public.