Kevin Freeman (defendant) was charged with conspiracy to possess cocaine with the intent to distribute. At trial, the prosecution called Bob Shin, a police detective, as an expert witness. The district court permitted Shin to testify as an expert witness about the meaning of certain coded drug-related language used in Freeman’s phone conversations. Shin also testified as a lay witness about the meaning of certain statements made on the calls that did not use drug jargon, but that the jurors could reasonably understand on their own. For example, Shin testified that when someone on a call used the phrase “get all the particulars,” the person meant to get all the details. The district court did not instruct the jury on Shin’s dual roles as both an expert witness and a lay witness. Freeman did not request this jury instruction either. Freeman was convicted, and he appealed.