Bruno v. State
In Bruno v. State, 845 S.W.2d 910 (Tex.Crim.App. 1993), the appellant claimed that the true owner of the vehicle gave him permission to use her vehicle.
Although a defensive instruction on mistake of fact was given, the appellant complained that doing so incorrectly placed the burden of proof on him.
The Court of Criminal Appeals found that the charge as given properly placed the burden on the State, but went on to find that the instruction was not necessary in the first place because a mistake of fact instruction was not proper when the issue was whether or not the true owner did or did not give permission to operate the vehicle.
A plurality of three judges of the Court of Criminal Appeals concluded that an instruction on mistake of fact was unnecessary in a prosecution for unauthorized use of a motor vehicle.
There, the appellant testified that the owner gave him her car, but the owner testified that the appellant grabbed her keys and drove away.
The charge required the jury to find that the appellant intentionally or knowingly operated the vehicle without the owner's effective consent.
The plurality explained that a mistake instruction need not have been given because "the jury could not believe both the testimony of the owner and the testimony of appellant," and the jury "would have necessarily been required to disbelieve appellant's story before they could find sufficient evidence to convict." Id.
Three other judges concurred, agreeing that "the mistake of fact instruction was unnecessary in the instant case." Id. (Baird, J., concurring).