In Commonwealth v. D.M., the SJC reversed the single justice’s denial of the Commonwealth’s petition for relief from an interlocutory order of the Juvenile Court, requiring the Commonwealth to reveal the identity of an informant. The facts are as follows. “Acting on information provided by a confidential informant, the Boston police apprehended, searched, and arrested the juvenile, D.M., on firearm-related charges. Before a pretrial suppression hearing in the Juvenile Court, the juvenile sought an order requiring the Commonwealth to disclose the identity of its informant and other related information. The Commonwealth asserted that it was privileged not to disclose the information, … because disclosure would jeopardize the informant’s safety. It averred that the informant was not a percipient witness to the juvenile’s arrest, and that the juvenile had not met his burden of demonstrating that disclosure was required…. The judge allowed the juvenile’s motion. The judge determined that … the juvenile adequately had challenged the assertion of the privilege on the ground that it interfered with his right to present a defense…. The judge concluded that the ‘informant’s identity and concomitant information are sufficiently “relevant and helpful to the defense of an accused” that it must be disclosed.’ The Commonwealth thereafter filed an appeal …, seeking reversal of the interlocutory ruling…. The single justice denied the petition, and the Commonwealth appeal[ed].”

In its decision in favor of the Commonwealth, the SJC reasoned that the judge erred in failing “to distinguish between ‘the need for disclosure of an informant’s identity at a pretrial suppression hearing and at the trial proper.’ (‘nondisclosure is rather readily countenanced at pre-trial hearings, but not so at the trial itself’).” “The distinction between ‘a demand for disclosure at a pretrial hearing, where the issue is probable cause for arrest or search, and a demand for disclosure at trial, where the issue is the defendant’s ultimate guilt or innocence,’ is an important one that long has been maintained.          Because the judge’s analysis conflated the two standards, … the analytical error should not stand…. While we recognize that a trial judge has considerable discretion in striking a balance, exercise of that discretion must be within the confines of the correct legal framework…. In these exceptional circumstances, we conclude that the single justice abused her discretion in declining to employ the court’s power of superintendence to rectify the error.”