Alvarado-Vasquez v. People & Rodriguez-Ortiz v. People (Amicus)

The ACLU of Colorado joined the Innocence Project and the Korey Wise Innocence Project to submit Amici Briefs in support of challenges to the admissibility of firearm toolmark analysis.

Firearm Toolmark Analysis (FATM) is a process by which forensic experts claim they can match ammunition to a particular gun by examining the marks made by the barrel of the gun on the spent ammunition components when the gun is fired. This method is based in two unsubstantiated claims: that each gun leaves unique, but reproducible markings on ammunition when fired, and that experts can determine exactly which firearm produced the markings. In fact, numerous peer-reviewed, scientific studies have shown that these conclusions are not supported by empirical testing. In recent years, courts across the country have recognized that this analysis and subsequent testimony should be limited. Experts should be permitted only to testify to the class characteristics of the firearm used, like the make, model, or caliber, but not the link between spent ammunition and a specific gun.

The ACLU of Colorado joined the Innocence Project and the Korey Wise Innocence Project as Amici Curiae, filing two briefs in the Colorado Supreme Court, arguing that firearm toolmark analysis is not admissible under the Colorado Rules of Evidence and People v. Shreck. The precedent set in Shreck demands barring testimony linking a specific gun to spent ammunition: cross-examination cannot effectively undermine an expert whose testimony is presented as scientific fact, and jurors are ill-equipped to question conclusions from a court-approved, government-employed forensic scientist. Amici request that the Supreme Court limit FATM testimony to opinions that the spent ammunition comes from a gun with certain class characteristics, and at most, that a specific firearm “cannot be excluded” as having fired ammunition. As other courts have increasingly recognized, such limitations are protective against inaccurate evidence and unfair verdicts.

“Colorado Supreme Court accepts cases about reliability of gun-to-bullet matching,” The Denver Gazette, February 14, 2026.