JUSTICE COOK delivered the opinion of the court:

Defendant, Arthur Cotton, appeals his jury convictionand sentence for unlawful delivery of a controlled substance witha prior conviction for unlawful possession of a controlledsubstance, a Class 2 felony. See 720 ILCS 570/401(d) (West2000). We affirm.

The testimony at defendant's trial showed the following. On April 27, 2000, police were conducting an undercoveroperation to identify street-level drug dealers in the city ofDecatur, Illinois. Officer David Crawford was working undercoverdriving a pickup truck around, trying to buy drugs. OfficerCrawford stopped at a curb, defendant approached the truck,Officer Crawford gave defendant $20, and defendant gave OfficerCrawford a rock of crack cocaine. A hidden video camera insidethe truck captured an image of defendant standing by the driver'sside window of the truck, but the actual drug transaction wasbelow the camera's frame and not captured on film. Other undercover officers who were conducting surveillance observed defendant approach the driver's side of the truck for a moment andthen walk away. These other officers did not observe the actualexchange of drugs or money. Immediately after the transaction,Officer Crawford met with Officer Jeff McClain and gave OfficerMcClain the crack cocaine he just purchased from defendant. Officer McClain delivered the crack cocaine to the crime lab,which confirmed that it was crack cocaine. Based on this evidence, the jury returned a verdict finding defendant guilty ofunlawful delivery of a controlled substance.

Defendant was convicted of a Class 2 felony, for whichthe normal sentencing range is three to seven years in prison. See 730 ILCS 5/5-8-1(a)(5) (West 2000). Because of defendant'sprior conviction for unlawful possession of a controlled substance, defendant was subject to a doubling of the maximumsentence, up to 14 years in prison. See 720 ILCS 570/408(a)(West 2000). At the sentencing hearing, the State recommended a10-year sentence. Defendant's counsel argued for a minimumsentence. The trial court sentenced defendant to seven years inprison based upon defendant's very extensive criminal historyspanning three decades. Defendant filed posttrial motionschallenging his conviction and sentence, which were denied. Defendant appeals.

II. ANALYSIS

Defendant raises the following arguments on appeal: (1) he was not eligible for an extended sentence because hisprior conviction was not presented and proved to the jury, (2)the evidence was insufficient to prove him guilty beyond areasonable doubt, and (3) he is entitled to a credit of $945against his fines. We address each issue in turn.

A. Defendant's Sentence

On appeal, defendant argues that we should vacate hissentence and remand for a new sentencing hearing because defendant was entitled to have the jury determine beyond a reasonabledoubt whether he had a prior conviction for unlawful possession. Without this determination, defendant argues, he was ineligiblefor the discretionary doubling of his maximum sentence pursuantto section 408(a) of the Illinois Controlled Substances Act (Act)(720 ILCS 570/408(a) (West 2000)). In support of his argument,defendant cites People v. Racinowski, 78 Ill. App. 3d 954, 960,397 N.E.2d 932, 937 (1979), which held:

"Where a criminal statute specifically provides that a previous conviction mandates enhancing the sentence or raising the degree of the offense, such previous conviction must be alleged in the indictment and proven to the fact finder." (Emphasis in original.) 

However, the application of section 408 of the Act doesnot require pleading or proving a prior conviction because theenhanced penalty is not mandatory. People v. Bradford, 187 Ill.App. 3d 903, 921, 543 N.E.2d 918, 930 (1989). Section 408(a) ofthe Act provides that "[a]ny person convicted of a second orsubsequent offense under this Act may be sentenced to imprisonment for a term up to twice the maximum term otherwise authorized." (Emphasis added.) 720 ILCS 570/408(a) (West 2000). There was no error here.

B. Sufficiency of the Evidence

Defendant also argues that we should vacate his conviction and sentence because the evidence was insufficient to provehim guilty beyond a reasonable doubt. The standard for reviewingthe sufficiency of the evidence in a criminal case is whether,when viewing the evidence in the light most favorable to theprosecution, a rational trier of fact could have found theessential elements of the crime beyond a reasonable doubt. People v. Brown, 169 Ill. 2d 132, 152, 661 N.E.2d 287, 296(1996); Jackson v. Virginia, 443 U.S. 307, 319, 61 L. Ed. 2d 560,573, 99 S. Ct. 2781, 2789 (1979). A reviewing court will notoverturn the fact finder's verdict unless the evidence is sounreasonable, improbable, and unsatisfactory as to leave areasonable doubt as to the defendant's guilt. Brown, 169 Ill. 2dat 152, 661 N.E.2d at 296. It is the reviewing court's duty toset aside a conviction when the evidence leaves a reasonabledoubt of defendant's guilt. People v. Schott, 145 Ill. 2d 188,206, 582 N.E.2d 690, 699 (1991); People v. Minniweather, 301 Ill.App. 3d 574, 577, 703 N.E.2d 912, 914 (1998).

In this case, the direct evidence against defendantcame in the form of the testimony of Officer Crawford, whoengaged in the drug transaction with defendant. "The testimonyof a single witness, if it is positive and the witness credible,is sufficient to convict." People v. Smith, 185 Ill. 2d 532,541, 708 N.E.2d 365, 369 (1999). Officer Crawford was positivein his identification of defendant, and his story was corroborated by the circumstantial evidence of the videotape and testimony of other officers who saw defendant standing by OfficerCrawford's pickup truck at the time of the transaction. TheState also proved that the item that defendant sold to theofficer was crack cocaine. Based on this evidence, a rationaljury could have found the essential elements of the crime beyonda reasonable doubt.

Defendant suggests the evidence was insufficientbecause Officer Crawford made four drug transactions that day,and the State could not confirm that the drugs introduced attrial did not come from one of those other three transactions. The testimony of Officer Crawford and Officer McClain, however,positively identified the crack cocaine introduced at trial asthe same cocaine purchased from defendant. Defendant alsosuggests that the evidence is contradictory because OfficerMcClain said he met Officer Crawford at the police station afterthe drug transaction with defendant, but Officer Crawford saidthey met on a different street. We do not find that this minordiscrepancy about what happened after the sale impugns theveracity of Officer Crawford's testimony about what happenedduring the sale. Finally, defendant suggests that the evidenceagainst him is suspect because no one searched Officer Crawfordto make sure he did not already have crack cocaine on his personbefore the alleged transaction with defendant. However, sinceOfficer Crawford was not an "addict-informer," but a policeofficer, a search of Officer Crawford's person prior to thetransaction was not necessary to bolster Officer Crawford'scredibility. See People v. Coles, 217 Ill. App. 3d 1079, 1087-88, 578 N.E.2d 86, 91 (1991).

C. Credit Against Defendant's Fine

At the sentencing hearing, the trial court imposed a$1,000 mandatory drug assessment and a $20 street-value fine. The court also determined that defendant was entitled to a $945credit against the fines. All of these fines and credits arereflected in docket entries in the record. Defendant thereforereceived the credit. There was no error here.

III. CONCLUSION

We affirm defendant's conviction and sentence.

Affirmed.

APPLETON and McCULLOUGH, JJ., concur.