As a result of an incident in a grocery store, Larry E. Estes was arrested. Estes filed this action pursuant to 42 U.S.C. § 1983 alleging that he was arrested without probable cause and that excessive force was used in arresting him. Defendant police officer Aaron Moore counterclaimed. A trial was held on the issues, and the jury returned a verdict against Estes on his § 1983 claims and returned a verdict in favor of Moore on the counterclaim awarding $1.00 in damages. The district court 1 denied Estes’s motion for new trial. Estes appeals.
I.
After observing Estes fall to the floor in a grocery store, a store employee called 911. Estes asserts that he had suffered an epileptic seizure. Firefighters Captain George Amen, Marvin Bauer, and John Hibberd *163 were the first to respond to the call and attempted to assist Estes. As Estes came to, he pulled off the heart monitor and pushed away the oxygen equipment. The ambulance service then arrived and proceeded to render aid to Estes. Estes sat up and became verbally abusive. Estes walked away but then returned to retrieve his wallet. A firefighter approached Estes and asked him to sign a form indicating that he was refusing assistance. Using profanity, Estes refused. When Jackie Schleich, a paramedic from the ambulance service, approached Estes to repeat the request, Estes angrily moved towards her. Police officer Moore stepped between the two, and Estes began to walk away. Moore twice tried to stop Estes by grabbing his arm so that he could speak with him. Estes swung at Moore and then threw him into a produce display. After further struggle, Moore handcuffed Estes. Because Estes was kicking, Moore and another officer, Michael Marvin, placed leg restraints on him. Estes was arrested and taken to jail. Estes asserts that he suffered a carpal tunnel injury to his wrist as a result of the handcuffs.
Estes argues that the district court erred in denying his motion for new trial. Estes also asserts that the district court abused its discretion in limiting the testimony of Estes’s expert witness and excluding evidence of Moore’s alleged negligence. We affirm.
II.
Estes argues that a new trial should have been granted because the evidence did not support findings that probable cause for the arrest existed, that Moore did not use excessive force in effectuating the arrest, and that Estes used unlawful force against Moore. The decision whether to grant or deny a motion for a new trial rests in the sound discretion of the trial court.
Morgan v. City of Marmaduke, Ark,
First, wé disagree with Estes’s argument that probable cause did not exist. When Moore stopped him by grabbing his arm, the stop was merely investigatory and not an arrest which requires probable cause.
See Terry v. Ohio,
III.
The district court sustained an objection to allowing Estes’s expert to testify as to whether probable cause for the arrest existed. Estes argues that the district court could not exclude the expert testimony just because it went to the ultimate issue in the case.
See
Fed.R.Evid. 704(a). Expert opinion testimony is only admissible if it “assists the trier of fact to understand the evidence or determine a fact in issue.”
See
Fed.R.Evid. 702. While the existence of probable cause is a mixed question of law and fact, the ultimate conclusion is a question of law.
United States v. Campbell,
IV.
For the reasons stated above, we affirm the judgment of the district court.
Notes
. The Honorable Warren K. Urbom, Senior United States District Judge for the District of Nebraska.
