Booth sends Brennan to question the dance class children because he can't question them without a parent present. By instructing her to do so Booth is making her an "agent of the State" which subjects any information she collects subject to the same rules of evidence as Booth.
A character references Wanda Holloway, calling her the Texas cheerleader mom who took out her daughter's competition. Holloway tried to hire a hitman to kill the mother of her daughter's rival, not the rival herself, and no one was killed.