Curtis v. State (1977)
In Curtis v. State, 548 S.W.2d 57 (Tex. Crim. App. 1977) on an appeal from a motion to revoke community supervision, the State made a similar argument.
There, the Court of Criminal Appeals rejected the State's sufficiency of the evidence argument that was based solely upon an experienced officer's testimony that the substances he seized field-tested positive for a controlled substance. Curtis, 548 S.W.2d 57 at 58-59.
The court concluded that, without the substantiating testimony of the chemist who lab-tested the seized substances, field testing was not enough to meet a preponderance of the evidence standard. Id. at 59.