delivered the opinion of the court:
The defendant was found guilty by a jury of the unlawful sale of a narcotic drug (Ill. Rev. Stat. 1967, ch. 38, par. 22 — 3). He was sentenced to ten to twenty years imprisonment in the State Penitentiary. He appeals from that conviction on the following grounds: that the prosecutor’s questions concerning the reporting of his business income were prejudicial, that he was deprived of a fair trial by the court’s failure to give an instruction on an element of the crime charged and by the prosecutor’s improper argument, that the restriction of cross-examination *865of the State’s informer denied him his sixth amendment rights, and that reversal is required because of false testimony by the informer and suppression of her criminal record.
On July 23, 1968, Augustus Stanfield, a Chicago policeman, arranged a controlled sale of narcotics with one Sylvia Carter (known by him to use several aliases), who was a drug addict and former prostitute. She told Officer Stanfield that the defendant would sell narcotics to her and, after making a phone call, she announced that she had arranged a $40 purchase. After she had been searched for narcotics by a policewoman, the woman was given $40 by Officer Stanfield, who had recorded the numbers of the bills. The woman was then taken by Officers Stanfield and Nance to the vicinity of a tavern where she said she had arranged by phone to meet the defendant. Officer Stanfield left the police car and positioned himself across the street from the tavern entrance. He observed the woman walk to the tavern entrance and signal someone inside. A man came out and the officer saw their hands come together twice. After making a prearranged sign that the sale had been made, the woman returned to the police car, where Officer Nance was sitting. She gave him a packet which he field-tested for heroin. The test was positive and he and Officer Stanfield then entered the tavern and arrested the defendant. The defendant had $172 on his person, $40 of which was the money given to the woman. The defendant testified that he had responded to a call from the bartender in the tavern, who placed an order for barbecued food from the store which the defendant owned, and that, after arriving at the tavern with his wife and delivering the order, the defendant remained inside until the police arrived.
The defendant first contends that a series of questions on cross-examination of him by the State constituted admission of evidence of a crime for which he was not charged. The challenged testimony consisted of questions as to the dollar amount of sales at the defendant’s barbecue store. The defendant’s responses indicated he kept no income records and he could only guess at the average sales figures. The crux of the defendant’s challenge to this testimony is the following exchange:
“Q. Did you pay any income tax that year? 
A. No, sir, the man that we got the barbecue place from was taking care of all that, because he owned the barbecue place before we got there, understand.
Q. All right, now, do you know that people pay income tax on money that they make?
A. Yes, sir.
■ Q. Did you make out any income tax returns for the year 1968?
*866MR. MISSIRLIAN: Your Honor, I am going to object.
THE WITNESS: The man that owned the tavern was taking care of that.
THE COURT: I am going to sustain the objection.
THE WITNESS: The one that owned the barbecue—
THE COURT: You don’t have to answer.
MR. DRISCOLL: Q. You don’t have any idea how much money you made that year?
THE WITNESS: A. No, sir, I don’t.
Q. You kept no records?
A. No, sir, we didn’t keep any records, because we was just starting.
Q. You started in September, 1967, is that right?
A. Yes, sir, he turned the barbecue place over to me and my wife, and he was paying the taxes, or whatever it was.
Q. All right, you have answered my question. Now, you had been in operation for ten months, is that right?
A. That’s right.
Q. You had no records of any of the amounts of sales or transactions that you made in the ten months that you were in operation?
A. Only nightly, that is all I can say.
Q. I am sorry, I didn’t hear what your answer was?
A. I say I could only answer that would be nightly, because we take in maybe $100 or $150, so we figured pretty good, that’s all.”
The defendant claims that this is evidence of the crime of income tax evasion, the admission of which was so prejudicial as to require reversal. We cannot agree. In the first place, we find in the quoted testimony no indication that taxes were evaded. The defendant testified that someone else paid them. Even if it were possible to draw an inference of income tax evasion from the cross-examination, we would not find such an inference prejudicial. Such an inference could not have affected the result in this case in view of the overwhelming evidence of the defendant’ s guilt. (People v. Scott, 52 Ill.2d 432, 288 N.E.2d 478; People v. Johnson, 2 Ill.App.3d 1067, 278 N.E.2d 177.) The cases cited by the defendant do not compel a different conclusion.
The defendant also challenges comments made by the prosecutor in closing argument on the ground that they prejudiced his case. In thé first of these comments, the prosecutor accused the defendant of being a dope pusher. This, the defendant argues, was equivalent to accusing him of committing crimes other than the one charged, because it implies *867that he sold narcotics to others. The contention is without merit. A single illegal sale of narcotics makes the seller a pusher, and that was the offense with which the defendant was charged.
The defendant goes on to allege that the prosecutors comments in argument were so inflammatory as to be prejudicial. Specifically, he refers to the characterization of the female informer as a walking corpse and of the defendant as a ghoul. The claim is made that the cumulative effect of these statements amounts to plain error, requiring reversal. But the general rule is that it is always proper to argue the evil results of a crime, urge the fearless administration of justice and denounce the accused’s wickedness if such statements have a basis in the facts in evidence or may fairly be inferred therefrom. (People v. Durso, 40 Ill.2d 242, 239 N.E.2d 842.) Even if this test had not been met, the comments would not be grounds for reversal, in light of the overwhelming evidence of guilt. People v. Davis, 46 Ill.2d 554, 264 N.E.2d 140; People v. Clay, 1 Ill.App.3d 736, 274 N.E.2d 843.
The defendant also contends that the prosecutor’s comment on his faflure to produce any witnesses from among the crowd in the tavern on the night in question was prejudicial. But such comment has been held to be proper where the defendant testifies as to his activities with a witness in order to show his innocence of the crime charged. (People v. Durso, 40 Ill.2d 242, 239 N.E.2d 842; People v. Beck, 133 Ill.App.2d 356, 273 N.E.2d 169.) Such is the case before us. Moreover, reversal is not required where such comment was not a material factor in the defendant’s conviction. People v. Nilsson, 44 Ill.2d 244, 255 N.E.2d 432.
The defendant next argues that faflure to instruct the jury that knowledge of a violation of the law is essential to find one guilty of unlawful sale of narcotics was error. While it is true that failure to include knowledge as a part of the instructions was error (People v. Mills, 40 Ill.2d 4, 237 N.E.2d 697), it was only harmless error, since the evidence as to defendant’s knowledge was so clear and convincing as to preclude a reasonable doubt of guilt. People v. Truelock, 35 Ill.2d 189, 220 N.E.2d 187.
The defendant cites a case in this court where reversal of a narcotic sale conviction was ordered on the ground that absence of a “knowledge" instruction raised a reasonable doubt as to the defendant’s guilt. (People v. Castro, 1 Ill.App.3d 537, 274 N.E.2d 839.) But as the court pointed out, the doubt arose because the defendant’s knowledge of the contents of the package he possessed was made a major question of fact. The defendant there contended he was only delivering the package and that he did not know its contents. The defendant here, on the other hand, never brought this issue before the court. He contends he never had the nar*868cotic in his possession. Hence, failure to instruct the jury as to the element of knowledge did not prejudice the defendant.
The next argument put forth by the defendant is that the.cross-examination of the female informer, Sylvia Carter, was so unduly restricted as to deny him his sixth amendment rights. The general rule is that the limits of cross-examination are set at the discretion of .the trial judge. Reversible error, if any, must be based on an abuse of that discretion. (People v. Clay, 1 Ill.App.3d 736, 274 N.E.2d 843.) The point at which cross-examination was restricted after objection by the State, sustained by the court, was when the female informer was asked where she purchased narcotics to support her $14 a day habit. We find no abuse of discretion in the court’s action. The question asked of an employed woman (she worked as a cook) as to the source of her narcotics (she admitted being an addict) was irrelevant to the case and had no. bearing on her credibility as a witness. While the widest latitude should be granted in the cross-examination of an addict-informer (People v. Soto, 64 Ill.App.2d 94, 212 N.E.2d 353), it need not encompass the admission of irrelevant testimony. The question could only be relevant here if the police were the source of her drugs. Subsequent testimony in this case established that the witness never received drugs or other favors from the police.
The defendant urges us to apply the reasoning of a case in which reversal was ordered because the addict-informer was allowed not to answer questions concerning the method of sustaining his habit. (People v. West, 3 Ill.App.3d 106, 278 N.E.2d 233.) This is not the case before us. The court in West found reversible error in the sustaining of an objection to the question of whether the witness supported his habit, by stealing. The habit was expensive, the witness was unemployed and he claimed no privüege for his refusal to answer. Questions as to his source of funds were relevant in establishing his credibility. The question in this case as to where the witness purchased her drugs could, as we have pointed out, be relevant only if the police were her source, and they v/ere eliminated as a source in subsequent testimony.
The defendant’s next argument is that he was prejudiced by suppression of the informer’s names and criminal record and by her false testimony. There are three parts to this argument. First, the defendant contends that the informer perjured herself. Second, he contends that the State knowingly suppressed information that should have been revealed to the defendant. Third, he contends that this non-disclosure amounted to. a deprivation of his right to confront the informer.
In support of the first contention, the defendant asserts that the female informer perjured herself because the names she gave in response *869to a question did not include either her name given at birth or the name under which she had been arrested several times. The fact is, however, the defense counsel never asked her for her given name. When she was asked by the State about her aliases, she gave three besides the name Mary Lou Wilkes; on cross-examination she said that she had used several names, possibly more than the ones listed. Defense counsel did not pursue the matter further. Nor did he pursue further questioning about her arrest record after asking if she had been arrested by Officer Stan-field or by an officer who knew Officer Stanfield. We will not disturb the final judgment of the trial court unless there is clear and convincing evidence that testimony alleged to be perjurious was indeed, perjurious. (People v. Bracey, 51 Ill.2d 514, 283 N.E.2d 685.) There is no such clear and convincing evidence to support the defendant’s argument.
The defendant next asserts that the State deliberately suppressed the felony record of the female informer, thus preventing the defendant from using it for impeaching purposes. The record discloses that the State did not reveal the informer’s given name nor did it reveal the significance of the name “Sylvia Lake” under which the informer was arrested several times. But the record also reveals that the State witness, Officer Stan-field, as early as the hearing on the motion to suppress, gave “Sylvia Lake” as one of two of the witness’s aliases, and there is no evidence that he or any State witness knew her given name. That the State did not reveal the significance of the name “Sylvia Lake” is not error, where the defendant has not shown that the information sought (her felony record) could not be obtained without knowing that significance.
As to the suppression of the informer’s felony record, the defendant asserts that he was thereby deprived of the opportunity to impeach her testimony. The State asserted that there was nothing in the witness’ criminal history which could be used for impeachment. The police record of the informer was included in the record in this casé after we granted the State leave to file it in a supplementary record. This procedure is in line with that suggested in special concurrence of Mr. Justice Stouder in a case involving the suppression of pretrial statements. (People v. Wilkes, 2 Ill.App.3d 626, 276 N.E.2d 761.) It is weHsettled that only certain convictions are admissible to impeach a witness’ testimony. (People v. Jackson, 95 Ill.App.2d 193, 238 N.E.2d 196.) There is no such conviction in the record pertaining to the informer here. Hence, we cannot find that the failure of the State to disclose it was prejudicial to the defendant’s case.
The defendant’s third contention under this argument is that failure to reveal the informer’s true name deprived him of his right to confront the witnesses against him. We find no merit in this argument. *870The defendant was given the name the informer used, as well as several aliases. Over fifteen aliases appear in the criminal record presented by the State. Not knowing all of these names did not change the fact that the defendant knew who the informer was and where she lived and worked. He had every opportunity to cross-examine her on the stand. It cannot be said that he was deprived of any constitutionally protected right to interrogate the witness. The cases he cites for a contrary finding are inapposite to the facts before us.
For the reasons stated, the judgment is affirmed.
GOLDBERG, J., concurs.