42 U.S. Code § 10503 - Limitation on authority
(a) Federal investigations
Nothing in this chapter authorizes the use of Federal law enforcement personnel to investigate violations of criminal law other than violations with respect to which investigation is authorized by other provisions of law.
(b) Federal supervision
Nothing in this chapter shall be construed to authorize the Attorney General or the Federal law enforcement community to exercise any direction, supervision, or control over any police force or other criminal justice agency of an applicant for Federal law enforcement assistance.
(c) Racial balance in criminal justice agencies
Nothing in this chapter shall be construed to authorize the Attorney General or the Federal law enforcement community—
(1) to condition the availability or amount of Federal law enforcement assistance upon the adoption by an applicant for such assistance of, or
a percentage ratio, quota system, or other program to achieve racial balance in any criminal justice agency of such applicant.
(d) Federal supplantation of State funds
No funds provided under this chapter may be used to supplant State or local funds that would otherwise be made available for such purposes.