((a)) ** In general** No benefit shall be paid under this subchapter—

((1)) if the fatal or catastrophic injury was caused by the intentional misconduct of the public safety officer or by such officer’s intention to bring about his death, disability, or injury;

((2)) if the public safety officer was voluntarily intoxicated at the time of his fatal or catastrophic injury;

((3)) if the public safety officer was performing his duties in a grossly negligent manner at the time of his fatal or catastrophic injury;

((4)) to any individual who would otherwise be entitled to a benefit under this subchapter if such individual’s actions were a substantial contributing factor to the fatal or catastrophic injury of the public safety officer; or

((5)) with respect to any individual employed in a capacity other than a civilian capacity.

((b)) ** Presumption** In determining whether a benefit is payable under this subchapter, the Bureau—

((1)) shall presume that none of the limitations described in subsection (a) apply; and

((2)) shall not determine that a limitation described in subsection (a) applies, absent clear and convincing evidence.