Jeffery Just v. Nellie Kuykendall, 7 F.4th 761

On July 7, 2017, Jeffrey Just returned to his disabled truck and found an unknown man (John Doe) rifling the console; Just called 911.
Officers Kuykendall and Henry arrived ~30–45 minutes later; a third party and John Doe told officers that Just had chased John Doe while brandishing a knife.
While asking for an officer’s name, Just was handcuffed, patted (no knife found), placed in a squad car; officers later handcuffed John Doe as well; both were released within an hour and no charges were filed.
Just sued under 42 U.S.C. § 1983 for Fourth Amendment false arrest and First Amendment retaliatory arrest; the district court denied the officers’ qualified-immunity summary-judgment motion.
The officers appealed interlocutorily; the Eighth Circuit reviewed whether, as a matter of law, probable cause or arguable probable cause existed at the time of the detention/arrest.
The Eighth Circuit held that the officers had probable cause (or at least arguable probable cause) to arrest Just for fourth-degree assault under Missouri law and therefore were entitled to qualified immunity on both the Fourth and First Amendment claims.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether officers had probable cause to arrest/detain Just for assault	No probable cause: Just called 911, John Doe not credible, no charges filed	Witnesses (John Doe and third party) said Just chased John Doe with a knife; John Doe voluntarily returned and was credible—facts gave probable cause for Mo. assault in the fourth degree	Court held as a matter of law that probable cause or arguable probable cause existed; qualified immunity applies
Whether arrest was unlawful First Amendment retaliation	Arrest motivated by Just asking for officer name (protected speech)	Even if retaliatory motive, existence of probable/arguable probable cause defeats claim	Court held retaliatory-arrest claim fails because probable/arguable probable cause existed; qualified immunity applies

Devenpeck v. Alford, 543 U.S. 146 (warrantless arrest reasonable if probable cause exists for any offense)
District of Columbia v. Wesby, 138 S. Ct. 577 (probable cause is an objective standard)
Nieves v. Bartlett, 139 S. Ct. 1715 (retaliatory-arrest claim requires lack of probable cause except narrow objective-evidence exception)
Anderson v. Liberty Lobby, 477 U.S. 242 (materiality standard for factual disputes on summary judgment)
Ross v. City of Jackson, 897 F.3d 916 (probable-cause analysis for warrantless arrests)
Quraishi v. St. Charles Cnty., 986 F.3d 831 (qualified immunity two-step review)
Sok Kong v. City of Burnsville, 960 F.3d 985 (appellate jurisdiction: reviewability of qualified-immunity denials)