(A)
In any investigation of—
(i)
(I)
a Federal health care offense; or
(II)
a Federal offense involving the sexual exploitation or abuse of children, the Attorney General; or
(ii)
an offense under section
871 or
879, or a threat against a person protected by the United States Secret Service under paragraph (5) or (6) of section
3056, if the Director of the Secret Service determines that the threat constituting the offense or the threat against the person protected is imminent, the Secretary of the Treasury,
may issue in writing and cause to be served a subpoena requiring the production and testimony described in subparagraph (B).