Mass. Gen. Laws ch. 94C, § 36

Notwithstanding the provisions of section thirty-five, if a police officer finds a child present where said officer finds a substance which he reasonably believes to be a controlled substance listed in Class A, B, or C of section thirty-one kept or possessed in violation of any provision of this chapter, and if the police officer reasonably believes that the child has not reached his eighteenth birthday and that the child knew of the presence of such controlled substance, the police officer may lawfully take such child into protective custody for a period not to exceed four hours. Persons having custody of a child under this section shall make reasonable efforts to notify the child's parent or guardian or other person having lawful custody. Such persons shall be considered to be acting in the conduct of their official duties and shall not be held criminally or civilly liable for such acts. A child detained pursuant to the provisions of this section shall not be considered to have been arrested or to have a criminal record for any purpose; however, only a departmental record of custody shall be made by the officer indicating the circumstances of custody. The procedures and processes provided by this section for the care, protection, and custody of children are not exclusive but are in addition to all others provided by law.