---
title: "Law Enforcement Expert May Provide Testimony about the National and SLMPD Standards for the Use of Pepper Spray"
meta:
  "og:description": "Law enforcement expert may testify about SLMPD and national police standards for the use of pepper spray, as long as he does not opine that the use of force was unreasonable"
  "og:title": "Law Enforcement Expert May Provide Testimony about the National and SLMPD Standards for the Use of Pepper Spray"
  author: "Expert Witness Profiler"
  description: "Law enforcement expert may testify about SLMPD and national police standards for the use of pepper spray, as long as he does not opine that the use of force was unreasonable"
---

# Law Enforcement Expert May Provide Testimony about the National and SLMPD Standards for the Use of Pepper Spray

Posted on April 4, 2025 by Expert Witness Profiler

Rev. Darryl Gray is suing the City of St. Louis and two St. Louis Metropolitan Police Department (SLMPD) detectives—Ronald Vaughan and Larry Wentzel—for violating his First and Fourth Amendment rights, as well as a variety of state law torts. 

To support his constitutional claims, Rev. Gray hired [Greg Meyer](https://expertwitnessprofiler.com/expert-witness/Gregory-Meyer/1529139) to give his expert opinion on some of the issues in the case. 

Meyer’s expert report sets out his extensive experience in law enforcement, and Defendants do not challenge his qualifications. Instead, Defendants filed a motion to exclude five opinions in Meyer’s report as unreliable and not helpful to the jury.

## **Law Enforcement Expert Witness**

[Greg Meyer](https://expertwitnessprofiler.com/expert-witness/Gregory-Meyer/1529139) has 47 years of law enforcement experience, including 33 years as a police tactics and procedures consultant.

He has been an expert witness in numerous high-profile cases including Rodney King, Oscar Grant (the Oakland BART murder case), and George Floyd. He has been engaged in more than 400 civil and criminal cases as well as conducting outside independent reviews of use of force cases for a federal prosecutor and several district attorneys and police chiefs.

[Discover more cases with Greg Meyer as an expert witness by ordering his comprehensive Expert Witness Profile report.](https://expertwitnessprofiler.com/order/add?eId=1529139&amp;pId=3)

## **Discussion by the Court**

#### **Opinions 2 and 3 are excluded because the City was granted summary judgment**

Opinions 2 and 3 in Meyer’s report relate to Rev. Gray’s [_Monell_](https://mwhlawgroup.com/taming-the-monell-monster/)claims against the City of St. Louis.

After the motion to exclude was filed, the Court granted summary judgment to the City on Rev. Gray’s _Monell_ claim. Opinions 2 and 3 in the report are therefore excluded because they will not “help the trier of fact to understand the evidence or to determine a fact in issue.” 

### **Meyer’s Opinions**

Meyer’s first opinion is:

“If the “Defendants’ actions violated Plaintiff’s First Amendment rights to freedom of speech and freedom of assembly by interfering with Plaintiff’s ability to associate freely in public and express Plaintiff’s views as part of a peaceful demonstration” as described in Para. 89 of the Second Amended Complaint, then the Defendants’ actions did not conform with proper contemporary law enforcement procedures.”

Meyer’s fourth opinion is:

“If Plaintiff did not push or otherwise assault or engage in preassault indicators against Defendant Vaughan’s allegedly pushing Plaintiff and using pepper spray on Plaintiff, and Officer Wentzel’s allegedly tackling Plaintiff to the street, did not conform with SLMPD policy or contemporary law enforcement training or procedures, and the resulting arrest and prosecution of the Plaintiff was false and malicious.”

Meyer’s fifth opinion is:

“If Plaintiff Gray did not assault Detective Vaughan, then both Detective Vaughan and Officer Wentzel appear to have violated SLMPD use of force policy and generally accepted police procedures when Detective Vaughan pepper sprayed Plaintiff Gray at extreme close range (inches); and Officer Wentzel used unnecessary and unreasonable force on Plaintiff Gray when he took him to the ground.”

#### **Opinion 1 is Excluded Because it is not Helpful to a Jury**

Defendants argued that his opinion will not be helpful to the jury because it is not based on “any specialized, scientific, or technical knowledge.” They claimed that the opinion says nothing more than “if the officers did it wrong, then they did it wrong.” The Court agrees with the Defendants.

Meyer’s opinion as formulated in his report tells the jury only that if Defendants’ conduct violated Rev. Gray’s First Amendment rights, then it did not conform with contemporary law enforcement procedures. 

The Court ruled that Meyer’s first opinion does not provide any additional insight into police practices that might be helpful to the jury. His rationale for Opinion 1 makes that clear. The police procedures and practices he cites are a restatement of First Amendment law. Meyer does not even opine that he thinks Defendants’ conduct violated the First Amendment under the circumstances. He admits that the facts are disputed, and he cannot determine who is correct.

#### **Opinions 4 and 5 are Excluded to the Extent that they State Legal Conclusions**

In Opinion 4, Meyer’s analysis of law enforcement training is just a description of the Fourth Amendment and Supreme Court precedent. The Court determined that Meyer relied on the Constitution and Supreme Court precedent to form opinions on questions of law that will not “help the trier of fact to understand the evidence or to determine a fact in issue.”

In his rationale for Opinion 5, Meyer goes into more detail about SLMPD policy and accepted police procedure on the use of pepper spray but provides no analysis for his opinion that “Officer Wentzel used unnecessary and unreasonable force on Plaintiff Gray when he took him to the ground.”

Plaintiff argued that Meyer’s opinions are not legal conclusions because they provide “the jury with a framework for placing the jury’s own findings in the context of national police standards and SLMPD policies.”

 In his rationale for Opinion 5, Meyer discussed the SLMPD’s and the International Association of Chiefs of Police’s (IACP) standards for pepper spray and opines that Detective Vaughan’s use of pepper spray did not comply with those standards. SLMPD and IACP standards are not common knowledge for jurors, and Meyer’s testimony will help contextualize the evidence the jury will hear about Detective Vaughan’s use of pepper spray.

Although Meyer’s report also states that Detective Wentzel’s “alleged tackling [of] Plaintiff to the street[] did not conform with SLMPD policy or contemporary law enforcement training or procedures,” the Court held that Meyer does not provide similar insight into accepted police procedure for that kind of force.

## **Held**

The Court granted in part the Defendants’ motion to exclude Plaintiff’s expert, Greg Meyer.

## **Key Takeaway:**

If Meyer had relied on SLMPD or IACP standards for uses of force like Wentzel’s, or _explained_ why, based on his own extensive law enforcement experience, he believes Wentzel could have used less force to control Rev. Gray, the opinion might be admissible. But without that information, the Court cannot properly assess whether the opinion satisfies  [Rule 702](https://www.law.cornell.edu/rules/fre/rule_702#:~:text=Rule%20702%20sets%20forth%20the,is%20a%20relatively%20narrow%20inquiry.)‘s requirements.

## **Case Details:**

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