The Confrontation Clause is violated by introduction of a laboratory report through testimony of a surrogate scientist. Petitioner was convicted of a DUI in New Mexico. Over a confrontation objection, the prosecution had introduced a laboratory report establishing petitioner’s blood alcohol content through a surrogate scientist who did not conduct the test. The New Mexico Supreme Court found no confrontation clause violation because the scientist who performed the test was a “mere scrivener” who transcribed machine results and the testifying scientist was an expert witness with respect to the gas chromatograph. However, the Confrontation Clause does not permit the prosecution to introduce a forensic laboratory report containing testimonial certification, through the testimony of an analyst who did not sign the certification or perform or observe performance of the tests, unless the declarant is unavailable and the defendant has had a prior opportunity to cross-examine.