¶1(concurring):
¶2I cannot accept the majority’s conclusion that the cross-examination of Mrs. Green and the subsequent “rebuttal” of the testimony thus elicited by the Commonwealth were proper. Nonetheless, applying the criteria formulated by this court in Commonwealth v. Conti, 236 Pa.Super. 488, 501, 345 A.2d 238, 245 (1975), I have concluded that the improper reception of the testimony in this non-jury trial was not prejudicial to appellants, and I therefore agree that the judgments of sentence should be affirmed.
¶4The majority acknowledges appellants’ contention that Mrs. Green was improperly impeached on a collateral matter, but pretermits discussion of that issue and, relying upon Commonwealth v. Quarles, 230 Pa.Super. 231, 326 A.2d 640 (1974), proceeds immediately to balance the probative value of Mrs. Green’s testimony against its prejudicial impact. I suggest that it is analytically premature to engage in the balancing process arguably (but I think in fact not) suggested by Quarles,
¶5I recognize that a party may present evidence to contradict testimony elicited by his own cross-examination of a witness. Commonwealth v. Hickman, 453 Pa. 427, 432, 309 A.2d 564, 567 (1973). However, this presupposes the propriety of the cross-examination. If a witness is improperly cross-examined concerning a collateral matter, the examiner is bound by the witness’s answers and may not contradict them. Hester v. Commonwealth, 85 Pa. 139 (1878); Hildeburn v. Curran, 65 Pa. 59 (1870); 2 G. Henry, Pennsylvania Evidence § 802, at *148258 (4th ed. 1953). This rule is applicable to cross-examination designed, as in the instant case, to affect the credibility of a witness. Commonwealth v. Graham, 170 Pa.Super. 343, 347, 85 A.2d 632, 634 (1952).
¶6The test of whether a matter inquired into on cross-examination is collateral is whether the examining party could prove the matter as part of his own case. Commonwealth v. Fisher, 447 Pa. 405, 413, 290 A.2d 262, 267 (1972); Commonwealth v. Zervas, 302 Pa. 510, 514, 153 A. 767, 768 (1931); Farms Appeal, 216 Pa.Super. 445, 451, 268 A.2d 170, 174 (1970). The Commonwealth cannot, on cross-examination, violate rules of evidence that restrict the presentation of its case-in-chief, i. e., it cannot do indirectly what it could not do directly. Commonwealth v. Burkett, 211 Pa.Super. 299, 302, 235 A.2d 161, 162 (1967).
¶7Viewed in light of these principles, it is apparent that the cross-examination of Mrs. Green concerned a collateral matter. The evidence of the discovery of the hypodermic needles and glassine bags could have permitted the fact-finder to infer that appellants were engaged in drug-related activity. The majority’s assertion to the contrary is refuted by the decisional law. See, e. g., Commonwealth v. Young, 222 Pa.Super. 355, 358-59, 294 A.2d 785, 787 (1972) (circumstances, which included purchase by defendant of one thousand glassine envelopes from stamp shop, “were replete with facts which suggested that defendant was associated with the illicit drug trade”). Thus, through the cross-examination of Mrs. Green, the Commonwealth was able to introduce evidence of other criminal activity on appellants’ part. Since it could not have presented such evidence in its case-in-chief, see, e. g., Commonwealth v. Burdell, 380 Pa. 43, 47, 110 A.2d 193, 195 (1955), the Commonwealth was bound by Mrs. Green’s denials, and should have been precluded from presenting Officer Burke’s rebuttal evidence.
¶8*149The majority contends that the evidence was offered for the legitimate purpose of discrediting the alibi witness. As previously noted, however, the rule barring inquiry into collateral matters on cross-examination applies with equal vitality to an attack upon a witness’s credibility. Commonwealth v. Truitt, 369 Pa. 72, 80, 85 A.2d 425, 429 (1951); Commonwealth v. Steinberg, 189 Pa.Super. 381, 385, 150 A.2d 131, 133 (1959); Commonwealth v. Graham, supra.Thus, for example, had appellants made an extrajudicial statement admitting their participation in the crime, the statement could have been introduced to contradict Mrs. Green’s alibi testimony, since the statement would be independently admissible as an admission of appellants. Commonwealth v. Tervalon, 463 Pa. 581, 590, 345 A.2d 671, 676 (1975). Similarly, had Mrs. Green made a prior statement to the police disclaiming knowledge of appellants’ whereabouts at the time of the crime, the statement could be introduced to discredit her alibi testimony. Commonwealth v. Farrior, 446 Pa. 31, 33, 35, 284 A.2d 684, 685, 686 (1971). See also Commonwealth v. Kettering, 180 Pa.Super. 247, 252-53, 119 A.2d 580, 583 (1956) (prior inconsistent statement). In short, there must be a basis for admissibility “independent of the contradiction.” Commonwealth v. Evans, 190 Pa.Super. 179, 251, 154 A.2d 57, 94 (1959), aff’d on the opinion below, 399 Pa. 387, 160 A.2d 407, cert. denied, 364 U.S. 899, 81 S.Ct. 233, 5 L.Ed.2d 194 (1960). There was no basis in the instant case for introduction of the incompetent evidence concerning appellants’ other criminal activity.
¶9II
¶10The majority attempts to buttress its conclusions by stating that, assuming inadmissibility of the evidence, “[t]he verdict of a judge, sitting without a jury, need not be nullified merely as a consequence of exposure to prejudicial evidence.” 243 Pa.Super. at 146, at 492 n. 7. *150This assertion disregards our recent decision in Commonwealth v. Conti, supra,and our observation in that opinion that “in some instances due process requires that we not simply rely on the fiction of a judicial blindside.” 236 Pa.Super. at 501, 345 A.2d at 245. In Conti, we
¶11Applying this test to the instant case, I do not think the judgments of sentence should be disturbed. Although the evidence of appellants’ unrelated criminal activity posed a risk of “emotional impact,” id.,the evidence, as the majority notes, was not explicitly and emphatically linked to appellants. The evidence of appellants’ guilt, consisting of the detailed testimony of the victim, who had known both appellants for a considerable period of time, was convincing. Therefore, since the incompetent evidence was not “so prejudicial and so vitally important to appellant [s’] case that we cannot presume [the trial judge] succeeded [in disregarding the incompetent evidence],” Conti, supra, at 503, 345 A.2d at 246, I join in the affirmance of the judgments of sentence.
¶12. Quarlesprovides scant support for the analytical framework endorsed by the majority. First, the court in Quarlesexplicitly declined to balance probative value against prejudicial effect since “no objection was made at trial, and the propriety of testimony was not attacked in the defendant’s post-trial motions.” 230 Pa.Super. at 235, 326 A.2d at 641. Second, the court expressed grave misgivings about the admission of evidence of drug addiction, observing that such evidence is “ ‘pregnant with prejudice.’ ” Finally, the testimony concerning the defendant’s drug addiction in Quarleswas relevant to the discrepancy in the defendant’s physical appearance between arrest and trial, while in the instant case the evidence concerning the hypodermic needles and glassine envelopes is irrelevant to the offenses with which appellants were charged.
¶13Quarlesshould be kept distinct from a case with an identical name that deals with issues unrelated to those presented by the instant case. Commonwealth v. Quarles, 229 Pa.Super. 363, 324 A.2d 452 (1974).
¶14. JACOBS and PRICE, JJ„ dissented.
¶15. Commonwealth v. Green, 464 Pa. 557, 347 A.2d 682 (1975), does not undercut this court’s analysis in Conti, and should be narrowly confined to its facts. In Green, the suppression judge found appellant’s confession to be voluntary. At his non-jury trial, appellant again raised the voluntariness issue, as permitted by Pa. R.Crim.P. 323(j). The trial judge, who was different from the suppression judge and sat as trier of fact, found the confession involuntary, and stated that he had disregarded it in adjudging appellant guilty of murder in the second degree. Mr. Justice Pomeroy in his majority opinion observed (Manderino, J., filed a dissenting opinion in which Roberts, J., joined) that the two-step procedure contemplated by Rule 323 was approved by the United States Supreme Court in Jackson v. Denno, 378 U.S. 368, 84 S.Ct. *1511774, 12 L.Ed.2d 908 (1964). Significantly, Mr. Justice Pomeroy noted that “[w]e are thus not faced with a situation where the same judge in the first instance determined both voluntariness and guilt.” 464 Pa. at 562 and n. 2, 347 A.2d at 684 and n. 2.