For the purpose of this subchapter, the term “law enforcement officer” means—
(1)
a law enforcement officer within the meaning of section
5541
(3) and to whom the provisions of chapter 51 apply;
(2)
a member of the United States Secret Service Uniformed Division;
(3)
a member of the United States Park Police;
(4)
a special agent in the Diplomatic Security Service;
(5)
a probation officer (referred to in section
3672 of title
18); and
(6)
a pretrial services officer (referred to in section
3153 of title
18).