This is only the tip of the iceberg, read the whole story. The chapter on Whitey Bulger damns Robert Mueller and his involvement.
When Pan Am 103 exploded on December 21, 1988, it was carrying Defense Intelligence Agency (DIA) officer, Charles McKee, along with his fellow officers.
Mueller was appointed as chief investigator of the bombing of Pan Am 103. His investigation overlooked a mountain of evidence, including the Iranian payments to Jabril before and after the crime for bombing an American plane.