41 CFR 301-31.1: -31.1 Purpose of subsistence and transportation expenses for threatened law enforcement/investigative employees.

To protect law enforcement/investigative employees and their “immediate family” (as defined in § 300-1.1 of this subtitle) when their lives are placed in jeopardy as a result of the employee's assigned duties. The agency may, on a case-by-case basis, expand the definition of “immediate family” to include other members of the employee's and/or the employee's spouse's or domestic partner's extended family.