## Facts

- Two armed bank robberies occurred in California: a Berkeley “takeover” robbery (Sept. 5, 1991) and a San Leandro robbery (Sept. 19, 1991), both involving masked perpetrators and a silver handgun; cash was taken by the gunman going behind the teller counter.
- A witness saw the San Leandro robbers leave, roll up ski masks, and flee in a light blue Ford/Mercury, providing a license plate number.
- Police traced the plate to a seller who said she sold the car to Keith Wayne Quinn and produced a bill of sale bearing Quinn’s signature.
- Less than two hours after the San Leandro robbery, police went to an Oakland residence associated with Quinn and saw the suspect Mercury with the reported plate and an Oldsmobile known to be driven by Quinn.
- After surveillance, Quinn and Robert Stewart exited the residence, entered the Oldsmobile, and began backing out of the driveway.
- Officers stopped the car at gunpoint, ordered both men to the ground, handcuffed them, and conducted a pat-down; officers found cash on Stewart and a bag of cash on the Oldsmobile’s front seat.
- Police secured the residence while obtaining warrants, then searched the house and the Mercury, finding cash (including bait bills from the San Leandro robbery), a loaded silver revolver, and ammunition.
- At trial, the government presented FBI Agent Douglas Goodin as a photogrammetry expert to estimate the Berkeley robber’s height from surveillance photos; he testified the robber was about 5'3" to 5'6", and Quinn was 5'5".
- Quinn was tried twice; the first trial ended in a hung jury, and the second resulted in convictions for two armed bank robberies and two firearm counts.

## Issues

1. Whether the Fourth Amendment required suppression because officers made a warrantless arrest in a nonpublic area when they stopped Quinn in a driveway with guns drawn and handcuffed him.
2. Whether the district court abused its discretion under Federal Rule of Evidence 702 by admitting photogrammetry testimony estimating the robber’s height from surveillance photographs, and whether a separate reliability hearing was required.

## Decision

- The court affirmed the convictions.
- The court held the warrantless arrest was lawful because officers had probable cause and the driveway stop as the vehicle was departing was treated as a public-place arrest.
- The court held the district court did not abuse its discretion in admitting the photogrammetry expert testimony and was not required to conduct a full separate evidentiary hearing on the method’s reliability.

## Legal Principles

- A warrantless arrest is permitted in a public place when supported by probable cause; a driveway stop as a suspect is leaving may qualify as a public-place arrest rather than an arrest within a protected home interior.
- Distinctions between in-home/threshold arrests and arrests in exposed areas can determine whether a warrant is required even when probable cause exists.
- Under Federal Rule of Evidence 702, technical or scientific expert testimony is admissible when grounded in testable, explainable principles and helpful to the factfinder; challenges to assumptions and measurement limits generally affect weight, not admissibility.
- A trial court has discretion in managing reliability screening for expert evidence; a separate, full-scale pretrial hearing is not automatically required for each specialized technique.

## Conclusion

The Ninth Circuit upheld Quinn’s warrantless driveway arrest based on probable cause and affirmed admission of photogrammetry testimony estimating a robber’s height from surveillance images, treating methodological criticisms as matters for cross-examination and jury evaluation rather than grounds for exclusion.


United States v. Quinn, 18 F.3d 1461 (9th Cir. 1994)