In Boyd v. Commonwealth, 213 Va. 52, 53, 189 S.E.2d 359, 359-60 (1972), the defendant was charged with possession and distribution of heroin after he sold two capsules of heroin to an undercover police officer. At trial, the officer was permitted to testify that a few days before the charged offense he observed Boyd making two similar drug sales. The trial court instructed the jury that the evidence of the prior offenses may not be considered as evidence of the defendant's guilt of the charged offense, but it may be considered as evidence "of whether the prior offenses constituted part of a general scheme, of which the crime charged is a part." The Supreme Court reversed the defendant's conviction, holding that the evidence of the prior sales was unrelated to the charged offense and the evidence of the prior sales did not fall within an exception to the general rule excluding prior crimes evidence. The Court concluded that because the evidence that Boyd had committed other crimes was not relevant, the prejudicial effect of the evidence outweighed its probative value.