Carsten James Quinlan; A.G.Q.; E.D.Q.; L.E.Q. v. Washington County

United States Court of Appeals
For the Eighth Circuit
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No. 25-2661
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Carsten James Quinlan; A.G.Q.; E.D.Q.; L.E.Q.
lllllllllllllllllllllPlaintiffs - Appellants
v.
Washington County; City of Woodbury; Kim Richardson; Hailey Dornfeld;
Keshini Ratnayake; Tom Wedes; Mathew Stephenson; Chris Murphy; Unknown
John and Jane Does
lllllllllllllllllllllDefendants - Appellees
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Appeal from United States District Court
for the District of Minnesota
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Submitted: March 12, 2026
Filed: March 17, 2026
[Unpublished]
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Before SHEPHERD, KELLY, and ERICKSON, Circuit Judges.
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PER CURIAM.
Carsten Quinlan appeals after the district court1 dismissed his pro se civil
action and denied his motion for leave to file a supplemental complaint. Upon careful
de novo review, we affirm.
We conclude that the district court did not err in dismissing the action, see
Schriener v. Quicken Loans, Inc., 774 F.3d 442, 444 (8th Cir. 2014) (grant of motion
to dismiss reviewed de novo), because the facts included in Quinlan’s operative
complaint and exhibits show his arrest was based on probable cause, see Brown v.
City of St. Louis, 40 F.4th 895, 903 (8th Cir. 2022) (Fourth Amendment claims based
on warrantless arrest fail when probable cause supported arrest and initiation of
prosecution), and because appellees did not infringe on his due process rights, see
Folkerts v. City of Waverly, 707 F.3d 975, 980–81 (8th Cir. 2013) (to state
substantive due process claim, plaintiff must show fundamental right was violated by
official conduct that shocks conscience); see also Mitchell v. Dakota Cnty. Soc.
Servs., 959 F.3d 887, 897 (8th Cir. 2020) (in child removal cases, due process
requires hearing “promptly after removal”).
We also conclude the district court properly denied Quinlan’s motion for leave
to supplement, because his proposed supplements would have been futile. See
Schriener, 774 F.3d at 446 (denial of leave to amend reviewed for abuse of discretion,
but underlying conclusion that amendment is futile reviewed de novo).
The judgment is affirmed. See 8th Cir. R. 47B.
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1The Honorable Katherine M. Menendez, United States District Judge for the
District of Minnesota.
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