JM 9-23.211
When determining whether to request immunity for a witness, consideration should be given to whether the witness is a close family relative of the person against whom the testimony is sought. A close family relative is a spouse, parent, child, grandparent, grandchild or sibling of the witness. Absent specific justification, the Department will ordinarily avoid seeking to compel the testimony of a witness who is a close family relative of the defendant on trial or of the person upon whose conduct grand jury scrutiny is focusing. Such specific justification exists, among other circumstances, where (i) the witness and the relative participated in a common business enterprise and the testimony to be elicited relates to that enterprise or its activities; (ii) the testimony to be elicited relates to illegal conduct in which there is reason to believe that both the witness and the relative were active participants; or (iii) testimony to be elicited relates to a crime involving overriding prosecutorial concerns.