The issue of whether the Commonwealth must disclose the identity of a confidential informant generally arises in two cases: where an informant provides probable cause for the issuance of a warrant; and non-warrant cases, where the informant is an eyewitness to the crime charged and the defense raises misidentification as its defense. 

The Commonwealth enjoys a qualified privilege that allows it to withhold the identity of a confidential informant.  In order to overcome this privilege, the defense must first establish the informant’s identity is material to the preparation of its defense.   Additionally, the defense must show the request is reasonable.

Once the defense satisfies its initial burden, the trial court is required to exercise its discretion and weigh relevant factors to determine if the Commonwealth should reveal the informant’s identity.  There is no single, determinative factor in deciding whether disclosure of the informant’s identity is required.  Instead, the court must focus on the particular circumstances of each case and take into account the crime charged, possible defenses, significance of the informant’s testimony, and any other relevant factors.  Although the balancing test is weighted in the Commonwealth’s favor, the privilege must give way if disclosure of the informant’s identity “is relevant and helpful to the defense or is essential to a fair determination of the case.”