People v. Tidd (2024) A167548 A167548; filed 8/29/24. ![[Files/CaseFiles/A167548.PDF]] [Opinion PDF](https://www.courts.ca.gov/opinions/archive/A167548.PDF) ## Rule excerpts Sargon foundation for this firearms toolmark opinion; no categorical rule excluding such evidence or decision on the Kelly test. > The People introduced no evidence that a firearm has a unique “signature or fingerprint,” no evidence that there is a reliable method a toolmark examiner can employ to determine whether two cartridge cases were fired in the same firearm, and no evidence that Swanepoel’s entirely subjective assessments were, in fact, reliable. The People, accordingly, provided no sufficient foundation for his opinion testimony. — People v. Tidd (2024) A167548, slip op., p. 18.