OPINION OF THE COURT
EAGEN, Chief Justice.On April 9, 1974, Gerald Nichols, appellant, was convicted by a jury of murder of the second degree, burglary, aggravated robbery, and other related offenses.1 After a denial of Nichols’ motions for a new trial and in arrest of judgment, judgments of sentence totalling twenty to forty years imprisonment were imposed.
No appeals were then entered. However, in 1976, post-conviction relief proceedings were instituted, and, after finding Nichols had not effectively waived his right to appeal from the judgments of sentence, the court entered an order permitting these appeals nunc pro tunc.2
Nichols seeks a new trial and, in part, complains the trial testimony of a Commonwealth police witness as to Nichols’ obstreperous conduct during a police lineup conducted in connection with a totally unrelated crime indicated to the jury he had been engaged in other criminal activity and thus prejudiced his right to a fair verdict of his guilt or innocence of the charges on trial.3
*4“In Pennsylvania, the law is clear that if a testimonial referenced absent specific circumstances,] . . .indicates to the jury the accused has been involved in prior criminal activity, reversible error has been committed.” Commonwealth v. Turner, 454 Pa. 439, 442, 311 A.2d 899, 900 (1973). This is not to say, however, that all references which may indicate prior criminal activity warrant reversal. For example, under certain circumstances, a defendant’s testimony may be impeached by showing prior convictions of felonies in the nature of crimen falsi, Commonwealth v. Bighum, 452 Pa. 554, 307 A.2d 255 (1973), and references to related criminal activity are allowable under certain circumstances.4 Further, “passing references” to prior criminal activity do not necessarily warrant reversal. See e. g., Commonwealth v. Irwin, 475 Pa. 616, 381 A.2d 444 (1977); Commonwealth v. McFadden, 464 Pa. 265, 346 A.2d 550 (1975); Commonwealth v. Sharpe, 449 Pa. 35, 296 A.2d 519 (1972). Rather, the record must illustrate that prejudice results from the reference. Prejudice results where the testimony conveys to the jury, either expressly or by reasonable implication, the fact of a prior criminal offense. Commonwealth v. Riggins, 478 Pa. 222, 386 A.2d 520 (1978); Commonwealth v. Banks, 454 Pa. 401, 311 A.2d 576 (1973).
The record discloses these relevant facts:
The crimes here involved occurred on March 23, 1972. The lineup referred to was conducted on March 30, 1972. According to a Commonwealth police trial witness, Nichols refused to cooperate, was forcibly placed in the lineup “with other inmates” by “prison guards,” threw himself on the floor during the lineup, and attempted to conceal his face.5
*5The Commonwealth admits that this lineup was conducted in connection with a totally unrelated crime and that, at the time of the lineup, Nichols was not yet charged with or in custody for the crimes here involved.6 However, pointing out these particular facts were not elicited at trial, the Commonwealth argues this background was “completely unknown to the jury,” and, hence, “the only reasonable inference available to the jury was that it [the lineup] resulted from” and was related to the crimes charged at trial and thus no prejudice resulted. It appears to us the Commonwealth underestimates the intelligence of a jury.
While the jury was not specifically informed the lineup concerned an unrelated crime, other testimony brought to the jury’s attention that Nichols was the “prime suspect” in the lineup and that it was viewed by only one witness, a female,7 to see if she could identify Nichols. Additionally, none of the Commonwealth trial witnesses in the case were of the female gender, and no indication exists in the record that a female witnessed these crimes. Further, evidence was presented to establish that the key Commonwealth witness, Ernest Vassallo, as late as the summer of 1972, was cooperating with authorities in an attempt to identify the felon through photographs. Given these facts, we cannot agree with the Commonwealth’s position that “the only reasonable inference available to the jury was that it [the *6lineup]” was conducted as to the crimes on trial. As we view it, the jury could, under the circumstances, reasonably infer prior unrelated criminal activity by Nichols.
Since the jury could reasonably have inferred Nichols was involved in other unrelated crimes from the evidence relating the March 30th lineup, prejudice resulted, and a new trial must be granted. Commonwealth v. Riggins, supra; Commonwealth v. Banks, supra.
Judgments of sentence reversed and a new trial is granted.
NIX, J., filed a concurring opinion.. The prosecution stemmed from the robbery of a retail market owned and operated by Ernest Vassalo in Philadelphia on March 22, 1972, during which a customer in the market was fatally assaulted by the felon.
. The appeal from the judgment imposed on the murder conviction was filed in this Court. An appeal from judgments of sentence imposed on the remaining convictions was filed in the Superior Court which certified that appeal to this Court.
. Nichols also argues, inter alia, that an inference of prior criminal activity arose during trial through the introduction into evidence of a “mug shot,” (showing a frontal and profile view of Nichols with all writing cropped away) taken of Nichols five days before the lineup and from a reference by a Commonwealth witness to photographs in police possession. Because of our decision, we need not discuss this issue.
. Instantly, we are not dealing with related crimes (see p. 1283, infra). Concerning the circumstances where references to related criminal activity are allowable, see Commonwealth v. Rose, 483 Pa. 382, 396 A.2d 1221 (1979); Commonwealth v. Fortune, 464 Pa. 367, 346 A.2d 783 (1975).
. Following this testimony, a motion for a mistrial was denied.
. Nichols was arrested in connection with the instant crimes on June 29, 1972.
. While the lineup was conducted for “a woman” and this was brought out by defense counsel on cross-examination, we must still consider it because it was essential for the defense to bring this fact to the jury’s attention.
We cannot hold the defense “responsible” for the introduction of this evidence, under the circumstances of this case, since the defense was forced to show that any inference of guilt from the conduct at the lineup was not an inference of guilt for the crimes sub judice. That is, the Commonwealth having introduced the evidence, the defense was left with two options: either say nothing and allow the possibility of an improper inference being drawn or attempt to defeat the inference. The latter being, we feel, the only reasonable course of action, we will not hold the defense responsible for the introduction of this evidence.