Burch v. State
In Burch v. State, 401 S.W.3d 634, 636 (Tex. Crim. App. 2013), the trial court admitted a lab report that the State had offered certifying that a substance found in the defendant's possession was cocaine. 401 S.W.3d at 635.
The State called the person who reviewed the report but not the person who tested or analyzed the substance. While the reviewer had signed off on the report, "there was no indication that she actually saw the tests being performed or participated in them." Id. at 635-36.
The Court of Criminal Appeals held that the defendant's Sixth Amendment right was violated because the evidence was testimonial and the defendant did not have an opportunity to confront the analyst who made the testimonial statement. Id. at 637-38 ("Without having the testimony of the analyst who actually performed the tests, or at least one who observed their execution, the defendant has no way to explore the types of corruption and missteps the Confrontation Clause was designed to protect against.").