In U.S. v. Olvis (4th Cir. 1996) 97 F.3d 739, the court examined the discriminatory-effect prong of the Armstrong test. After a police investigation of a large crack cocaine conspiracy, 25 Blacks were indicted on federal charges. There were 55 other people involved in the conspiracy, including five non-Blacks, who were not indicted. The defendants sought discovery of the government's prosecution criteria, alleging that at least three Whites had been granted immunity despite the fact that they were at least as culpable as the defendants, and that at least two Whites had not been charged. The government responded to the discovery motion, explaining that some of the Whites had agreed to help the prosecution, while there was insufficient evidence to indict the others. "Focusing only on the evidence of the conspirators' criminal activity, the [district] court found all to have 'similar involvement' in the conspiracy" and granted the defendants' discovery motion. (Id. at p. 744.) On appeal, the court of appeals reversed, explaining that "the district court in this case failed to take into account several factors that play important and legitimate roles in prosecutorial decisions. " (Ibid.) The court further explained: "Generally, in determining whether persons are similarly situated for equal protection purposes, a court must examine all relevant factors. . . . 'The goal of identifying a similarly situated class of law breakers is to isolate the factor allegedly subject to impermissible discrimination. . . . If all other things are equal, the prosecution of only those persons [to whom the factor applies] . . . gives rise to an inference of discrimination. But where the comparison group has less in common with defendant, then other factors . . . may very well play a part in the prosecution.' . . . . . Prosecutorial decisions may . . . be legitimately influenced by such factors as the strength of the evidence against a particular defendant, the defendant's role in the crime, . . ., the defendant's candor and willingness to plead guilty, the amount of resources required to convict a defendant, the extent of prosecutorial resources, the potential impact of a prosecution on related investigations and prosecutions, and prosecutorial priorities for addressing specific types of illegal conduct. Making decisions based on the myriad of potentially relevant factors and their permutations require the very professional judgment that is conferred upon and expected from prosecutors in discharging their responsibilities. . . . Defendants are similarly situated when their circumstances present no distinguishable legitimate prosecutorial factors that might justify making different prosecutorial decisions with respect to them." (Olvis, supra, 97 F.3d at p. 744; see also U.S. v. Magana (1st Cir. 1997) 127 F.3d 1, 8.)