United States v. Oviedo

Oviedo (defendant) sold a substance to an undercover agent as heroin, and a field test initially came back positive, leading to his arrest; a search of his home turned up more of the same substance, but later chemical analysis revealed it was actually procaine hydrochloride, an uncontrolled substance. Oviedo was charged with attempted distribution of heroin, and at trial testified he knew the substance wasn't heroin and was simply trying to swindle the agent for cash; the jury disbelieved him and convicted him regardless, and he appealed.