Failed Sobriety Tests and Probable Cause: Municipal Liability Requires an Underlying Constitutional Violation

1. Introduction

This case concerns the factual allegations necessary to maintain a civil-rights action following an intoxicated-driving arrest when criminal charges are later dismissed. Marwan M. Qashou alleged that police mistook the effects of his permanent back injury for intoxication. The Fifth Circuit nevertheless concluded that his complaint did not plausibly allege an unconstitutional arrest, excessive force, or a basis for municipal liability.

Officers Michael Strickland and Michaela Cannard stopped Qashou around midnight on May 21, 2023, while his eleven-year-old child was in the vehicle. Qashou admitted failing a field sobriety test but alleged that he had informed the officers that a permanent back injury prevented him from passing it. He also alleged that he explained that, as a practicing Muslim, he did not drink alcohol. Officer Strickland arrested him for driving while intoxicated with a minor child present.

Qashou requested a blood test, which allegedly returned negative. Crucially, however, he did not allege when the results became available or that any defendant knew them before his arrest, appearance before a magistrate, or release on bond. A magistrate set a $5,000 bond on the afternoon of the arrest; Qashou posted bond and was released two days later. All criminal charges were dismissed on August 28, 2023.

Qashou subsequently brought claims concerning his own rights and those of his minor child against the officers, the City of San Antonio, the San Antonio Police Department (“SAPD”), and Police Chief William McManus. The central questions were whether the complaint plausibly alleged a Fourth Amendment violation and, if not, whether related municipal and failure-to-train claims could survive.

2. Summary of the Opinion

The Fifth Circuit affirmed dismissal under Federal Rule of Civil Procedure 12(b)(6). Its principal conclusions were:

• Initial stop: A traffic stop requires reasonable suspicion, not probable cause or necessarily a warrant. Qashou supplied no supporting facts plausibly establishing that reasonable suspicion was absent.
• Arrest: On the pleaded facts, Qashou’s admitted failure of the field sobriety test supplied probable cause. A subsequently negative blood test did not retroactively invalidate that assessment.
• Excessive force: The complaint alleged no use of force by either officer, much less excessive force.
• Municipal liability: Without a plausibly alleged underlying constitutional violation, the policy-based and failure-to-train claims against the City and Chief McManus failed.
• Proper defendants: SAPD lacked the capacity to be sued, and the official-capacity claims against Chief McManus duplicated the claims against the City.

Although the opinion describes the complaint as asserting numerous state and federal claims, its substantive analysis focuses on the constitutional claims, municipal liability, and the legal status of the defendants. It does not separately develop the elements of individual state-law causes of action.

3. Precedents Cited and Their Influence

A. Pleading Standards and Appellate Review

Doe 1 v. City View Indep. Sch. Dist., 150 F.4th 668, 674 (5th Cir. 2025)

This decision supplies the standard of review: dismissal for failure to state a claim is reviewed de novo. The appellate court therefore independently assessed the complaint’s legal sufficiency rather than deferring to the district court’s analysis.

Bell Atlantic Corp. v. Twombly, 550 U.S. 544, 570 (2007)

Twombly requires enough factual content to make entitlement to relief plausible. Its role was foundational: invoking civil rights or characterizing an arrest as unlawful could not substitute for allegations explaining what made the defendants’ conduct unconstitutional.

Ashcroft v. Iqbal, 556 U.S. 662, 678 (2009)

Iqbal explains that pleaded facts must permit a reasonable inference of liability. The court relied on that distinction between factual allegations and legal conclusions when assessing the stop, arrest, and claims concerning both Qashou and his child.

Harmon v. City of Arlington, 16 F.4th 1159, 1162–63 (5th Cir. 2021)

This Fifth Circuit authority reinforces that conclusory statements are insufficient under Rule 12(b)(6). It supported rejecting generalized allegations of civil-rights violations where the complaint did not identify supporting unconstitutional conduct.

B. Reasonable Suspicion and Probable Cause

United States v. Breeland, 53 F.3d 100, 102 (5th Cir. 1995)

The court cited this decision for the rule that an objectively reasonable suspicion of illegal activity, including a traffic violation, can justify a vehicle stop. It corrected the complaint’s apparent assumption that the officers needed probable cause or a warrant merely to initiate the stop.

United States v. Walker, 49 F.4th 903, 907 (5th Cir. 2022)

Walker emphasizes that reasonable suspicion is a lower threshold than probable cause. This distinction allowed the panel to separate two constitutional questions: whether the officers could stop the vehicle and whether they could subsequently arrest its driver.

Florida v. Harris, 568 U.S. 237, 244 (2013)

The panel drew from this case the practical conception of probable cause as a “fair probability” on which reasonable officers may act. That standard does not require certainty of guilt. The court applied it to Qashou’s admitted failure of the field sobriety test.

Justice v. Austin Police Dept., A-20-CV-1063-RP, 2021 WL 1930302, at 3 (W.D. Tex. May 13, 2021)

This district-court decision provided the opinion’s most fact-specific support: failure to pass a field sobriety test can provide probable cause for arrest. It supplemented the general probable-cause principle drawn from Florida v. Harris; it was not itself binding appellate authority.

Bigford v. Taylor, 834 F.2d 1213 (5th Cir. 1988)

Qashou invoked this case on appeal concerning the alleged disregard of exculpatory evidence. The panel noted that he had not discussed it in his operative pleading and declined to consider it further, except to state that the record did not support an assertion that officers ignored exculpatory evidence.

The opinion therefore does not provide a developed interpretation of Bigford v. Taylor. Its footnote is best understood as rejecting this particular argument on the pleaded record, not as establishing a general requirement that complaints cite every potentially relevant precedent.

C. Municipal Liability and Failure to Train

Monell v. Dep't of Soc. Servs. of City of New York, 436 U.S. 658, 690 n.55 (1978)

Monell supplies the framework for municipal liability under 42 U.S.C. § 1983. A municipality is not liable merely because it employs an alleged wrongdoer; a constitutional injury must be connected to municipal policy or custom. The opinion also cited its discussion of official-capacity litigation when treating the claims against Chief McManus as duplicative.

Henderson v. Harris Cnty., Tex., 51 F.4th 125, 130 (5th Cir. 2022)

This case supplied the requirement that a constitutional violation be propelled by an official policy promulgated by a municipal policymaker. It underscores the causal connection required between municipal action and the asserted injury.

Windham v. Harris Cnty., Tex., 875 F.3d 229, 243 (5th Cir. 2017)

The court relied on this decision for the dispositive proposition that the absence of an underlying constitutional violation defeats the municipal claim. Because Qashou had not plausibly alleged such a violation, further examination of municipal policy was unnecessary.

City of Canton v. Harris, 489 U.S. 378, 388 (1989)

This decision establishes that inadequate training can support municipal liability when the inadequacy amounts to deliberate indifference. The opinion’s reference to a “Canton claim” denotes this failure-to-train theory, not a separate statutory cause of action.

Littell v. Houston Indep. Sch. Dist., 894 F.3d 616, 624 (5th Cir. 2018)

Quoting City of Canton v. Harris, this Fifth Circuit decision supplied the deliberate-indifference standard. It demonstrates why merely asserting that officers should have received better training does not establish municipal responsibility.

Collins v. City of Harker Heights, Tex., 503 U.S. 115, 123 (1992)

This authority links the employee’s constitutional violation, the municipality’s policy or custom of inadequate training, and causation. The panel emphasized the first requirement: without a sufficiently alleged constitutional injury, the training theory could not proceed.

D. Official-Capacity Claims and Capacity to Be Sued

Sanders-Burns v. City of Plano, 594 F.3d 366, 373 (2010)

The court cited this case to explain that suing a municipality can render an official-capacity claim against its officer redundant. It supported dismissal of the claims against Chief McManus as duplicative of those against the City.

Guillot ex rel. T.A.G. v. Russell, 59 F.4th 743, 751 (5th Cir. 2023)

This decision explains the underlying principle: an official-capacity suit is effectively a suit against the governmental entity for which the official acts. The panel used it to justify dismissal even though the district court had not separately addressed the chief’s position.

Darby v. Pasadena Police Dep't., 939 F.2d 311, 313 (5th Cir. 1991)

This case supported dismissal of SAPD because the department lacked independent capacity to sue or be sued. That defect concerned the department’s legal status, not the merits of the alleged misconduct.

E. The Underlying District-Court Decision

Qashou v. City of San Antonio, No. 5:25-CV-00459-JKP, 2025 WL 3461736, at *3 (W.D. Tex. Dec. 2, 2025), was cited to describe the claims the district court understood Qashou to assert. The district court had identified apparent excessive-force and unlawful-arrest theories despite uncertainty in the complaint. The appellate court independently agreed that neither theory was sufficiently pleaded.

4. Analysis of the Court’s Legal Reasoning

A. The Decision Turns on Pleading Sufficiency

The case ended before discovery or trial. The controlling question was not whether Qashou could prove intoxication never occurred, but whether the operative complaint plausibly alleged unconstitutional conduct by the defendants.

That distinction matters because dismissal did not establish that Qashou was intoxicated. Nor did it adjudicate the medical causes of his test performance. It established that the pleaded facts, including the admitted failed sobriety test, did not support the constitutional claims the panel considered.

B. The Initial Stop and the Arrest Required Separate Analysis

The court distinguished the lower reasonable-suspicion threshold for a traffic stop from the higher probable-cause threshold for an arrest. An allegation that officers stopped Qashou without probable cause or a warrant did not, by itself, address the governing standard for the initial stop.

The panel found no factual allegations supporting an inference that reasonable suspicion was absent. This was a pleading conclusion, not an affirmative factual determination identifying the traffic violation or other conduct that justified the stop.

C. Probable Cause Was Assessed at the Time of Arrest

The principal holding was that Qashou’s admitted failure of the field sobriety test supplied a fair probability supporting arrest. The court did not treat subsequent dismissal of the charges as proof that the original arrest was unconstitutional.

The negative blood test presented a related timing problem. The complaint did not allege that any defendant knew its result before arrest. Information obtained afterward cannot automatically alter what officers reasonably understood earlier. The absence of allegations about knowledge before the magistrate appearance or release also left the complaint without a developed factual theory based on defendants knowingly continuing detention despite those results.

The panel did not separately develop a prolonged-detention claim or decide doctrines governing responsibility after judicial proceedings begin. Its analysis remained focused on the deficiencies of this complaint.

D. Disability and Religious Observance Did Not Change the Pleading Outcome

Qashou’s disability allegation was potentially important because a physical limitation could offer a non-intoxication explanation for failing a physical test. His assertion that religious practice precluded alcohol consumption likewise supplied his account of why the officers’ inference was mistaken.

The court nevertheless held that these allegations did not plausibly establish unconstitutional conduct on the pleaded record. It did not provide a detailed assessment of the particular test, how the back injury affected performance, or how the officers evaluated that explanation.

The holding should therefore remain narrow: the opinion does not establish that disability is always irrelevant to probable cause, that officers may invariably disregard contrary information, or that every failed sobriety test conclusively establishes probable cause in every factual setting. Nor does it separately decide a disability-discrimination or religious-discrimination claim.

E. Excessive Force and the Child’s Claims Lacked Supporting Facts

The excessive-force theory failed at a basic factual level: no use of force was alleged. There was consequently no occasion to balance the severity or reasonableness of particular force.

The court also found no plausibly alleged constitutional violation against Qashou’s child. The child’s presence during the arrest did not itself identify an infringement of the child’s own constitutional rights. The opinion did not undertake a separate, developed analysis of any child-specific constitutional theory.

F. Municipal Liability Failed at the Constitutional-Injury Threshold

Municipal liability requires more than employment of the officers involved. A plaintiff must connect a constitutional injury to the municipality’s own policy, custom, or qualifying training failure.

Here, the analysis stopped at the first step: no underlying constitutional violation was plausibly pleaded. The court therefore did not need to determine whether the City maintained a relevant policy, whether training was actually deficient, or whether municipal policymakers acted with deliberate indifference.

This reasoning should not be confused with a rule that a municipality can never be liable unless a particular officer is personally liable. The panel’s stated ground was the absence of an underlying constitutional violation, not merely the absence of an individual damages award against an officer.

5. Potential Impact and Limits

For unlawful-arrest litigation, the opinion illustrates how facts pleaded by a plaintiff can undermine a claim. An admitted failed sobriety test may support probable cause unless the surrounding factual allegations plausibly establish why reliance on it was constitutionally unreasonable.

For cases involving later exculpatory evidence, timing and knowledge are critical. A negative test or dismissed prosecution does not alone establish that officers lacked probable cause earlier. Any theory based on later-acquired information must identify when it became available, who knew it, and what allegedly unlawful conduct followed.

For municipal-liability claims, the decision reinforces the need to plead the underlying constitutional injury before addressing policy, custom, or training. General accusations of inadequate training cannot repair a missing constitutional claim.

For party selection, the case highlights two recurring pitfalls: naming a police department without independent capacity to be sued and duplicating municipal claims through official-capacity claims against a police chief. The opinion does not separately assess a developed personal-capacity claim against Chief McManus.

Its broader influence is limited by its unpublished designation and its fact-specific pleading posture. It is most useful as an illustration of established doctrine, not as a categorical rule governing every disability-related sobriety-test dispute.

6. Complex Concepts Simplified

Rule 12(b)(6)

A procedure for dismissing a complaint that does not allege a legally sufficient, plausible claim. It is not a trial of disputed facts.

De novo review

The appellate court independently examines the legal question without deferring to the district court’s conclusion.

Reasonable suspicion

A fact-based, objectively reasonable basis to suspect wrongdoing sufficient for a brief investigative stop. It requires less than probable cause.

Probable cause

A practical assessment that there is a fair probability of criminal activity. It does not require certainty or proof sufficient for conviction.

Exculpatory evidence

Information tending to show that a person did not commit the suspected offense. Its significance to an officer’s decision depends partly on when the officer knew it.

Monell liability

Municipal responsibility for constitutional harm caused by the municipality’s own policy or custom, rather than automatic responsibility for employees’ conduct.

Deliberate indifference

A demanding standard beyond ordinary carelessness, relevant to whether a municipality’s failure to train can support constitutional liability.

Official-capacity claim

A claim against a public official in their governmental role, ordinarily functioning as a claim against the governmental entity itself.

Capacity to be sued

An entity’s legal ability to be a defendant. A municipal department does not necessarily possess that ability separately from its city.

7. Conclusion

Qashou v. City of San Antonio reinforces three established principles: probable cause depends on information available at the relevant time; civil-rights complaints require concrete factual allegations; and municipal liability requires an underlying constitutional violation.

The court treated the admitted failed sobriety test as supporting probable cause on this complaint and rejected the unsupported force and municipal claims. Its significance lies in that pleading analysis—not in declaring every failed sobriety test conclusive or every later exoneration legally irrelevant.