Code of Federal Regulations Title 36. Parks, Forests, and Public Property § 36.902.57 Investigatory files compiled for law enforcement purposes

(1) Interfere with enforcement proceedings;

(2) Deprive a person of a right to a fair trial or an impartial adjudication;

(3) Constitute an unwarranted invasion of personal privacy;

(4) Disclose the identity of a confidential source and in the case of a record compiled by a criminal law enforcement authority in the courts of a criminal investigation, or by an agency conducting a lawful national security intelligence investigation, confidential information furnished only by the confidential source;

(5) Disclose investigative techniques and procedures;  or,

(6) Endanger the life or physical safety of law enforcement personnel.