United States v. Conn

United States Court of Appeals for the Seventh Circuit · 2002 · Evidence

297 F.3d 548 (7th Cir. 2002)

Updated August 22, 2026

EvidenceRule 701Rule 702expert testimonylay opinionspecialized knowledgeDaubertKumho Tire

Facts

During a three-month undercover investigation, officers and agents acquired seven firearms from Conn on six occasions, and the transactions were recorded. After the investigation, agents searched Conn's home and seized 165 firearms and 10,000 rounds of ammunition, most located in one room. At trial, Conn's defense was that he was merely a firearms collector who made occasional purchases and sales to enhance his personal collection. The Government responded in part with ATF Agent McCart's testimony that, based on his training and experience, the firearms recovered were generally not collector's items.

Issue

Whether Agent McCart's opinion that Conn's firearms were not collector's items was specialized testimony that had to satisfy Rule 702, and if so, whether the district court abused its discretion by admitting it. The court also considered whether any inconsistency between acquittals on Counts 1 through 5 and conviction on Count 6, or alleged insufficiency of the evidence, required reversal.

Rule

Opinion testimony based on scientific, technical, or other specialized knowledge falls within Rule 702, not Rule 701, even when offered through a witness who also participated in the investigation. Under Rule 702, expert testimony is admissible if the witness is qualified by knowledge, skill, experience, training, or education, if the testimony is based on sufficient facts or data, if it is the product of reliable principles and methods, and if those principles and methods are applied reliably to the facts of the case. Experience and training can provide a sufficiently reliable basis for expert testimony, and inconsistent criminal verdicts are not a basis for reversal.

See the holding & full analysis

Create a free KwikCourt account to unlock the rest of this brief — and practice the case.

The court's holding and reasoning
Doctrine tests, pitfalls & exam hypotheticals
10 practice questions + 4 AI-graded essays on this case

Free sample · practice this case

Test yourself

One of 10 multiple-choice questions for this case. Pick an answer to see why.

In a federal fraud trial in Chicago, Postal Inspector Nora Velez testifies that hundreds of seized luxury watches were "counterfeit resale stock, not collectible timepieces." The prosecutor elicited that Nora based this conclusion on her agency training and years investigating counterfeit-goods markets, but argued the opinion was admissible as lay testimony because Nora personally observed the watches during the search.

How should the court classify Nora's opinion testimony?

Explanation. The governing rule is that testimony based on scientific, technical, or other specialized knowledge falls within Rule 702, not Rule 701. Even though Nora participated in the investigation and personally saw the watches, her conclusion about whether they were collectible or counterfeit resale stock relies on specialized market knowledge gained through training and experience. Under the majority opinion, such testimony cannot be admitted in "lay witness clothing."