OPINION
CAPPY, Justice.This Court granted allocatur in order to review the burdens of proof and the proper procedures in applying the CarterRoviaro test1 to criminal prosecutions where a confidential informant is an eyewitness to the crime and the defendant seeks the disclosure of the informant’s identity for purposes of preparing a defense at trial.
Appellant, Nathaniel Roebuck, was charged -with two counts each of Possession of a Controlled Substance, 35 P.S. § 780-113 (a) (16), Possession with Intent to Deliver, 35 P.S. § 780-113 (a) (30), Delivery of a Controlled Substance, 35 P.S. § 780-113 (a) (30), and Criminal Conspiracy, 18 Pa.C.S.A. § 903 in connection with two drug sales involving the use of a confidential police informant who was also an eyewitness to the transactions. The jury convicted Appellant of all the charges. Appellant took an appeal to the Superior Court. The Superior Court affirmed. For the reasons which follow, we vacate in part and affirm in part the order of the Superior Court.
A review of the record reveals the following. On December 21,1990, at or about 2:00 p.m., Detective Renee Kacsuta of the Pittsburgh Police Department met with a confidential informant for the purpose of making an undercover buy of narcotics. The informant drove Kacsuta to Mt. Pleasant Street in *474the Northview Heights section of Pittsburgh. According to Kacsuta, the seller, whom she later identified as the Appellant,2 approached the informant’s vehicle and leaned down toward the car window. Kacsuta testified that she leaned forward and greeted the seller. Thereafter the seller discussed with the informant a sale of a “bundle” of heroin. After quoting a price of $180, the seller walked up the street approximately fifty feet, where he met with an individual later identified as Keith Lee.3 Lee handed something to the seller, whereupon, the seller returned to the vehicle and handed to Kacsuta a plastic baggie containing fifteen balloons filled with heroin. In return, Kacsuta paid the seller the agreed price of $180. This entire episode lasted approximately fifteen minutes, during which Kacsuta was able to observe the seller’s appearance.
Immediately following the drug transaction, according to Detective Kacsuta, the informant told Kacsuta that the seller was Nathaniel Roebuck. Upon returning to police headquarters, Kacsuta entered the name of “Nathaniel Roebuck” into the BCI computer and received a description which matched that of the man whom she had observed during the drug transaction. Kacsuta also removed a photograph of Nathaniel Roebuck from the police identification office, and this she also identified as a photograph of the man from whom she and the informant had purchased the heroin.
Subsequently, on January 23, 1991, Detective Kacsuta returned to Mt. Pleasant Street, together with the informant, for the purpose of making another purchase of heroin from the seller. On this occasion, Kacsuta was driving her own vehicle and the informant was riding as a passenger. Upon their arrival at Mt. Pleasant Street, the seller approached the driver’s side of the vehicle and asked Kacsuta what she wanted. When Kacsuta told the seller she wanted a “bundle,” he replied that the price had gone up to $190. When Kacsuta *475responded affirmatively, the seller conferred with a man who was later identified as Albert Austin.4 Austin then entered two separate apartment buildings, and, upon emerging from the second building, approached Kacsuta’s vehicle and handed her a bundle of fifteen balloons which were filled with heroin. Kacsuta, in return gave Austin $190.
A criminal complaint was filed against Appellant on April 17, 1991, and he was arrested the following day. Appellant filed a pretrial discovery motion seeking disclosure of the confidential informant who had participated in the two undercover drug transactions which had led to his arrest. Appellant alleged that his defense at trial would be mistaken identification and expressed the belief that the informant’s testimony might be helpful. At a pre-trial hearing on this motion, Appellant testified that, on the day prior to his arrest on the instant drug charges, he had been picked up by police and questioned regarding an unrelated shooting incident because he had been misidentified by the victim of that shooting. Appellant also related an additional incident in which an acquaintance of his, Ivy Edwards, had observed in a police station a “wanted” poster which had Appellant’s picture on it, but which contained the name and description of another individual. Following the pre-trial hearing, the Court denied Appellant’s motion for disclosure of the identity of the informant.
At trial, Appellant testified that he had not been present at either drug transaction and denied that he had ever met Detective Kacsuta. He also testified regarding the prior misidentification of him in the unrelated shooting incident; and Ivy Edwards testified as to having observed the mislabeled photograph of Appellant at a police station. Appellant also called Albert Austin as a witness, and he admitted his participation in the transaction of January 23,1991, but denied that the other man had been Appellant. After hearing all the testimony, the jury rejected Appellant’s defense of misidentification and found him guilty of all charges.
*476PENNSYLVANIA RULE OF CRIMINAL PROCEDURE 305(B)(2)
The parties present this case as being governed by Pa.R.Crim.P. 305(B)(2)(a), pertaining to pretrial discovery,5 which provides in pertinent part:
(2) Discretionary With the Court. In all court cases, except as otherwise provided in Rule 263 (Disclosure of Testimony Before Investigating Grand Jury), if the defendant files a motion for pretrial discovery, the court may order the Commonwealth to allow the defendant’s attorney to inspect and copy or photograph any of the following requested items, upon a showing that they are material to the preparation of the defense and that the request is reasonable:
(a) the names and addresses of all eyewitnesses[.]
Thus, as the above quoted rule implies, an appellate court’s standard of review is to determine whether the Court of Common Pleas abused its discretion in denying a defendant’s request for discovery. See, e.g., Commonwealth v. Jones, 432 Pa.Super. 97, 103, 637 A.2d 1001, 1004 (1994).
Appellant essentially argues that he met his burden to show that the identity of the confidential informant is material to the preparation of his defense and that his request is reasonable. Appellant further argues that he has shown that his need for the identity of the confidential informant in order to assure a fair trial outweighed any privilege by the Commonwealth to maintain the confidentiality of the informant.
The Commonwealth, on the other hand, argues that Appellant did not meet his burden to show that the identity of the confidential informant was material to Appellant’s defense or that the request was reasonable. In addition, the Commonwealth argues that the trial court properly weighed Appel*477lant’s alleged need for the confidential informant’s identity against the Commonwealth’s qualified privilege to preserve the informant’s confidentiality in order to protect the flow of information from informants and thereby maintain the public’s interest in effective law enforcement.6 The Commonwealth argues that the trial court did not abuse its discretion in finding that the Appellant had failed to show that his need for information outweighed the Commonwealth’s privilege.
We note that pursuant to Pa.R.Crim.P. 305(B) there is a threshold requirement that Appellant make some showing that the information sought is “material” to the preparation of the defense and that the request is reasonable. Herein Appellant alleged that he was misidentified by Detective Kacsuta and he denied any participation in the events. He sought the identity of the confidential informant so as to corroborate his testimony. In support of his theory of misidentification, he offered testimony at the pretrial hearing that on the day he was arrested for the present charges he had been misidentified to the police by a person who accused Appellant of shooting him. As additional support for his defense of misidentification, Appellant offered testimony that the local police station had posted a picture of Appellant which had attached to it someone else’s name and a physical description which did not match that of Appellant.
In Commonwealth v. Payne, 540 Pa. 54, 60, 656 A.2d 77, 80, (1994) a case very similar to the present case, we observed that:
[t]he instant record reveals that Appellant testified at the evidentiary hearing that he had not met the trooper prior to *478his arrest and that he had not been at the apartment complex where the [drug] transaction occurred on the night in question. What is that if not “evidence that suggests that he was not at the scene?”.... This is precisely the kind of showing which we indicated in Carter would suffice to require disclosure. Where the defense is one of mistaken identity, the defendant can do no more than deny his involvement and suggest that another eyewitness might offer evidence that would support this claim.
In Payne, we went on to hold that the defendant’s conviction had to be vacated. Furthermore, “the defendant cannot be expected to predict exactly what the informant would say on the stand. Rather, in keeping with Roviaro and Carter, ‘all the defendant must show is a reasonable possibility that the anonymous informer could give evidence that would exonerate him.’ ” Commonwealth v. Pritchett, 225 Pa.Super. 401, 408, 312 A.2d 434, 438 (1973)(emphasis added). In light of the foregoing, Appellant has clearly provided evidence which suggests that he was not at the scene and that there was a reasonable possibility that the confidential informer could give evidence that would exonerate him. Accordingly, we conclude that Appellant has clearly made a showing that the information sought was indeed material. Furthermore, in light of the nature of the defense, ie., misidentification by Detective Kacsuta, the request for the identity of the confidential informant was reasonable.
Only after a showing by the defendant that the information sought is material and the request reasonable is the trial court called upon to exercise its discretion to determine whether the information is to be revealed. Commonwealth v. Bonasorte, 337 Pa.Super. at 355, 486 A.2d at 1374. In Commonwealth v. Carter, supra, this Court announced standards which should guide the trial courts in the exercise of their discretion in cases where the defendant requests the identity of a confidential informant who is also an eyewitness and, in response, the Commonwealth asserts its qualified privilege to maintain the confidentiality of the informant. In Carter, we adopted the *479guidelines which the United States Supreme Court announced in Roviaro v. U.S., supra:
[w]e believe that no fixed rule with respect to disclosure [of the confidential informant’s identity] is justifiable. The problem is one that calls for balancing the public interest in protecting the flow of information against the individual’s right to prepare his defense. Whether a proper balance renders the nondisclosure erroneous must depend on the particular circumstances of each case, taking into consideration the crime charged, the possible defenses, the possible significance of the informer’s testimony and other relevant factors.
Carter, 427 Pa. at 59, 233 A.2d at 287 (quoting Roviaro, 353 U.S. at 60-62, 77 S.Ct. at 628-29).
THE DECEMBER 21, 1990 CHARGES
Applying the foregoing standards to the charges of December 21, 1990, we are constrained to conclude that the trial court abused its discretion in denying Appellant’s request for the identity of the confidential informant. The confidential informer was the only eyewitness to the entire transaction other than Detective Kacsuta.7 Thus, the possible significance of the confidential informant’s testimony cannot be underestimated in this case. This clearly weighs in favor of disclosure. Payne, supra, Commonwealth v. Lloyd, 427 Pa. 261, 234 A.2d 423 (1967), Carter supra, and Commonwealth v. Lee, 254 Pa.Super. 495, 386 A.2d 59 (1978). Moreover, the fact that the only eyewitness to the entire transaction other than the confidential informant was a police officer militates in favor of *480disclosure. In Carter, 427 Pa. at 61, 233 A.2d at 288, we noted that:
[elemental to our concept of fairness,' as well as that embodied in the federal constitution, is the awareness that the testimonial perspective of police officers is conditioned by the “often competitive enterprise of ferreting out crime.” [citations omitted] This awareness make us reluctant to permit the establishment of facts crucial to criminal guilt solely by police testimony based on a single observation where testimony from a more disinterested source is available,8
Accord Payne, supra, and Lloyd, supra.
On the other side of the equation, a court should weigh, inter alia, the public’s interest in maintaining the flow of information to the police and the safety of the confidential informant. We note in this regard that there was no evidence whatsoever presented that disclosure would jeopardize the safety of the confidential informant or compromise any ongoing investigation. Accordingly, in light of the foregoing considerations which weigh in favor of disclosure and the fact that there has been no showing by the Commonwealth. of any countervailing considerations,9 the trial court clearly abused *481its discretion in failing to compel disclosure of the confidential informant’s identity. Accordingly, we vacate the judgement of sentence arising out of the December 21, 1990 charges and remand for further proceedings consistent with this opinion.
THE JANUARY 23, 1991 CHARGES
At the pre-trial evidentiary hearing, the trial court orally denied Appellant’s motion to produce the identity of the confidential informant. Implicit in this ruling is the judgement that Appellant failed to prove that his need for the confidential informant’s identity outweighed the Commonwealth’s privilege. We agree insofar as this conclusion relates to the January 23, 1991 charges and, thus, we cannot conclude that the trial court abused its discretion in finding that Appellant failed to prove that his need outweighed the Commonwealth’s privilege. The trial court stated, “I do not think that ... the Defense [i.e., Appellant] has made a showing that the Cl was in a position to have information which is critical to the defense such as to warrant the production of the Cl.” N.T. at p. 53 (May 28, 1992). We understand this to be a determination that in light of the fact that Albert Austin had made himself available to Appellant in order to testify that Appellant was not present at the January 23,1991 drug sale,10 which *482corroborated Appellant’s own testimony, Appellant failed to show that he needed the testimony of the confidential informant. U.S. v. Simonetti, 326 F.2d 614, 615 (2d Cir.l964)(no abuse of trial court’s discretion in denying disclosure where “the testimony of the Special Employee [i.e., the confidential informant] would have been at best cumulative.”); Suarez v. U.S., 582 F.2d 1007, 1012 (5th Cir.1978)(no error in denying disclosure where the informant’s testimony in Suarez was not essential to the appellant’s defense as was the case in Roviaro because the confidential informant therein represented the only likely source of exculpatory information.) Cf. Commonwealth v. Christy, 540 Pa. 192, 656 A.2d 877 (1995)(arguably erroneous exclusion of some evidence was harmless because other similar evidence was admitted and thus no prejudice); Henery v. Shadle, 443 Pa.Super. 331, 661 A.2d 439 (1995)(erroneous exclusion of evidence harmless where similar evidence was admitted).
Our conclusion that the trial court did not abuse its discretion in deciding that Appellant failed to prove his need for the information outweighed the Commonwealth’s privilege is bolstered by the actual testimony of Albert Austin at Appellant’s trial. Appellant essentially alleged that the testimony of the confidential informant would have corroborated his theory that Detective Kacsuta mistakenly identified Appellant as the seller. At trial, Appellant testified, and denied being present at the transaction or having ever met Detective Kacsuta. Albert Austin, who admittedly was present at, and involved in the transaction on January 23, and subsequently pleaded guilty to possession, delivery and conspiracy based on his participation therein, testified at Appellant’s trial that Appellant was not present or involved in any way with that transaction. At best, the confidential informant’s testimony would have merely duplicated Albert Austin’s testimony. In light of the fact that *483this testimony would have at best been cumulative of Albert Austin’s testimony, the trial court’s exercise of discretion in denying Appellant the information as it relates to the January 23,1991 charges was vindicated.
Accordingly, we affirm the judgement of sentence arising out of the January 23,1991 charges.
The order of the Superior Court is thus vacated in part and affirmed in part.
NEWMAN, J., files a concurring opinion in which NIX,
C.J., joins.
CASTILLE, J., files a concurring and dissenting opinion.
. Commonwealth v. Carter, 427 Pa. 53, 233 A.2d 284 (1967); Roviaro v. U.S., 353 U.S. 53, 77 S.Ct. 623, 1 L.Ed.2d 639 (1957)
. Apparently, Detective Kacsuta had never met Appellant prior to December 21, 1990.
. Keith Lee was also charged in connection with his role in this transaction. He was tried separately.
. Albert Austin was also charged for his role in this transaction. In a separate proceeding, he pleaded guilty to the charges.
. Both Appellant and the Commonwealth agree that Pa.R.Crim.P. 305(B)(2)(a) is the relevant provision. See Appellant’s Brief to this Court at 10-11; Commonwealth’s Brief to this Court at 10-11. The Superior Court below agreed. Commonwealth v. Roebuck, No. 1149 PGH 1993, slip op. at 5-6, 440 Pa.Super. 635, 654 A.2d 602. (Pa.Super. September 28, 1994). As the parties do not raise any other provision of the rules governing discovery, we neither consider nor decide whether other provisions would apply.
. In Commonwealth v. Carter, 427 Pa. at 56, n. 3, 233 A.2d at 285, n. 3 (1967), we stated that "neither statute nor appellate decision in Pennsylvania has yet recognized such a privilege” to refrain from disclosing the identity of confidential informers in criminal trials. Now however, there are appellate cases which clearly recognize and/or apply the privilege in this jurisdiction. See, e.g., Commonwealth v. Payne, 540 Pa. 54, 656 A.2d 77 (1994); Commonwealth v. Washington, 463 Pa. 206, 344 A.2d 496 (1975); Commonwealth v. Delligatti, 371 Pa.Super. 315, 538 A.2d 34 (1988), alloc. den., 520 Pa. 595, 552 A.2d 250 (1988); Commonwealth v. Speaks, 351 Pa.Super. 149, 505 A.2d 310 (1986); Commonwealth v. Bonasorte, 337 Pa.Super. 332, 486 A.2d 1361 (1984).
. Contrary to the Commonwealth's assertion that Keith Lee was an eyewitness, the record is devoid of any evidence that he saw or heard the initial encounter between Detective Kacsuta and the seller of the drugs when they exchanged greetings and when the informant and the seller negotiated the price. The record also establishes that at the time the seller actually handed the drugs to Detective Kacsuta and she paid him, Keith Lee, if he was still present, was at least 50 feet away from the spot where the exchange occurred. Moreover, at the time of Appellant's trial, Lee was under indictment for participation in this December 21st incident and Appellant reasonably asserts that Fifth Amendment concerns may have precluded Lee's availability as a witness at Appellant’s trial.
. In this case there were two observations of the seller made by Detective Kacsuta and, thus, this case differs from Carter in this regard. Arguably this weighs in favor of maintaining the privilege. However, this distinction is not legally determinative. See Commonwealth v. Lee, 254 Pa.Super. at 500, 386 A.2d at 61 (1978)(holding that the appellant therein showed a need for the information which outweighed the privilege. The court held this despite the fact that police observed the seller on three separate occasions within the span of 24 hours. On each occasion the informant was also an eyewitness. The Court found of particular significance the fact that the informant was the only "civilian” witness who actively participated in and witnessed the alleged drug transaction, and that the appellant therein produced alibi witnesses at trial.)
. The Commonwealth argues that it did not need to provide any evidence that disclosure would impair the flow of information or jeopardize ongoing investigations or endanger the informant because Appellant failed to meet his threshold burden of demonstrating that the informant's identity would materially aid his defense. We have found that Appellant did indeed meet this threshold and, thus, there was a need for the Commonwealth to present the required evidence.
. While Albert Austin did not testify at the preliminary hearing, it is clear that the judge knew of the existence of such a witness and the nature of that witness' testimony. In the course of a discussion between defense counsel, Ms. Middleman, and the court, where defense counsel was explaining what further witnesses she was going to present at the pretrial hearing, the court inquired if one of the witnesses to be presented at the pre-trial hearing was going to testify that Appellant was not present at the drug transactions:
THE COURT: The guy [i.e. the witness] is going to say he [Appellant] is not the guy [who sold the drugs]? j
MS. MIDDLEMAN: Well, I think I might save that for trial, Your Honor.
THE COURT: Okay.
N.T. at p. 30 (May 28, 1992). Moreover, the prosecution argued at the pre-trial evidentiary hearing that the availability of Albert Austin must be considered in the balancing test of Carter-Roviaro. The prosecution argued:
Thirdly, it appears on the record, I believe the Defense has available other witnesses to call for purposes of presenting whatever misidentification theory they have, that being both Keith Lee and, I *482believe, Howard [sic] Austin, who is present in the bullpen for that purpose.
Caselaw [sic] also indicates that the availability of other witnesses is to be considered in a weighing and balancing test, that if the other witnesses are available, the privilege can remain intact while the Defendant still presents his defense and has a fair trial.
N.T. at p. 50 (May 28, 1992).