## Facts

- Laurie Lynn Bartlett stabbed and killed her live-in boyfriend, Ernest Lamar, at their trailer and asserted self-defense based on battered-spouse syndrome.
- Investigator Mark Walton, the primary case agent, briefly spoke with Bartlett at the scene; she was crying and upset but appeared to have no physical injuries.
- Walton inspected the trailer with Bartlett’s permission, observed Lamar’s body, and identified a single stab wound to the chest as the apparent cause of death.
- Bartlett was charged with second-degree murder and filed notice of intent to rely on self-defense.
- At trial, the prosecution elicited testimony from Walton that, before signing the arrest complaint, he had “ruled out” self-defense; over defense objections, the court permitted Walton to explain the basis for that conclusion (including perceived inconsistencies between Bartlett’s account and physical evidence and comparisons to other self-defense incidents).
- The jury found Bartlett guilty of the lesser-included offense of manslaughter, and the court imposed ten years’ imprisonment followed by five years’ probation.

## Issues

1. Whether the trial court erred by allowing the lead investigator to testify that he had “ruled out” self-defense and to explain that conclusion.
2. If error occurred, whether the State proved beyond a reasonable doubt that the error did not contribute to the verdict under the *DiGuilio* harmless-error standard.

## Decision

- The appellate court held it was error to admit the detective’s opinion that he had “ruled out” self-defense and related explanatory opinion testimony because it intruded on the jury’s role to decide the self-defense claim.
- The court rejected the argument that any pre-charging duty to consider self-defense justified presenting the officer’s ultimate conclusion to the jury.
- The court held the error was not harmless; the State failed to show there was no reasonable possibility the testimony affected the verdict.
- The court reversed the conviction and sentence and remanded for a new trial.

## Legal Principles

- Lay opinion testimony, including from law-enforcement witnesses, is limited to opinions based on the witness’s perception that are helpful to understanding the testimony or deciding a fact in issue; it may not amount to an evaluative conclusion on an ultimate issue reserved for the jury (such as whether the defendant acted in self-defense).
- A lead investigator’s “bottom-line” assessment of a contested justification defense carries a risk of undue weight and may improperly substitute the officer’s judgment for the jury’s factfinding.
- Under *State v. DiGuilio*, the State bears the burden to prove beyond a reasonable doubt that an evidentiary error did not contribute to the verdict; the test is whether there is no reasonable possibility the error affected the outcome.

## Conclusion

The court ordered a new trial because the lead detective’s testimony that he had “ruled out” self-defense was improper opinion on the central disputed issue and the State did not establish beyond a reasonable doubt that the error played no role in the manslaughter verdict.


Bartlett v. State, 993 So. 2d 157 (Fla. Dist. Ct. App. 1st Dist. 2008)