Brenda Guadalupe Trevino v. State, 512 S.W.3d 587

On November 29, 2013 police were called after a 17-year-old was reported suicidal and in possession of a kitchen knife; Officer James O’Connor responded in uniform.
Officer O’Connor entered the bedroom to verify who had the knife and observed the sister with an arm hidden under a blanket; he twice announced in English and Spanish he needed to speak with her.
While officers restrained and handcuffed the sister to ensure safety and prepare for transport for an emergency mental-health detention, appellant vocalized objections and twice physically blocked officers’ movements (including planting herself in a doorway and later pushing an officer).
Officer O’Connor used minimal force to move appellant onto a chair so officers could escort the sister out; appellant was later arrested on a magistrate-issued warrant for Interference with Public Duties (Tex. Penal Code § 38.15), charged as having pushed the officer while he was conducting an investigation.
At trial the jury convicted appellant of the Class B misdemeanor; she appealed arguing (1) insufficient evidence that the officer was performing a statutory "investigation" and (2) the trial court erred by not sua sponte instructing the jury on the statutory speech-only defense.

Issue	Appellant's Argument	State's Argument	Held
Sufficiency: Was there evidence officer was performing a duty/exercising authority by conducting an "investigation" when pushed?	The officer was performing a "service"/mental-health transport, not an "investigation" under §38.15, so evidence is insufficient.	Health & Safety Code imposes a statutory duty to investigate emergency mental-health calls; the officer was investigating whether an emergency detention was justified.	Affirmed: Viewing evidence in prosecution's favor, a reasonable juror could find the officer was conducting a lawful investigation under the Health & Safety Code when appellant interfered.
Jury charge: Did the trial court have a duty to instruct sua sponte on §38.15(d) speech-only defense?	§38.15(d) bars prosecution for speech-only interference (First Amendment); court should treat it as law applicable to the case and give instruction sua sponte.	The speech-only provision is a statutory "defense to prosecution," not an exception or element; under Posey and Taylor it is a defensive issue and not required sua sponte.	Affirmed: No sua sponte duty. Speech-only is a defensive issue (statutorily labeled a defense) and trial court need not give it absent a timely request supported by evidence.

Jackson v. Virginia, 443 U.S. 307 (legal-sufficiency standard for criminal convictions)
Posey v. State, 966 S.W.2d 57 (Tex. Crim. App. 1998) (distinguishing "law applicable to the case" from defensive issues; courts need not give unrequested defensive instructions)
Taylor v. State, 332 S.W.3d 483 (Tex. Crim. App. 2011) (framework for deciding when statutory provisions are mandatory law vs. defensive issues)
City of Houston v. Hill, 482 U.S. 451 (First Amendment protects a significant amount of verbal criticism of police; speech-only restrictions problematic if overbroad)
Carney v. State, 31 S.W.3d 392 (Tex. App.—Austin 2000) (recognizing speech-only protection and that conviction requires evidence of physical conduct beyond mere speech)
Barnes v. State, 206 S.W.3d 601 (Tex. Crim. App. 2006) (discussing §38.15 speech-only provision as a statutory defense)