State v. Patterson, 344 Conn. 281

Early morning August 25, 2008: two men (Ortiz and Gresham) were shot and killed on Edwards Street; police recovered nine‑mm casings and bullets/fragments.
Cold case later developed leads; defendant Harold Patterson was arrested and charged in 2016 for the Edwards Street murders.
State sought to admit evidence of two prior June 2008 shootings (Acton Street and Mather Street) where eyewitnesses placed Patterson as the shooter and casings were later linked by ballistics to the Edwards Street scene via NIBIN and expert comparison.
Trial court admitted the uncharged‑misconduct evidence for limited purposes (means and identity), barred more inflammatory details (e.g., killing at Acton), and required the state to first tie casings to the Edwards Street evidence before identity could be argued.
Firearms expert Jachimowicz testified all casings/bullets across the three incidents were from the same semiautomatic; court instructed the jury on limiting uses of the prior‑incident evidence at least five times.
Defendant did not request a Porter hearing to challenge the scientific methodology; convicted of two counts of murder; conviction affirmed on appeal.

Issue	State's Argument	Patterson's Argument	Held
Admissibility/relevance of ballistics expert testimony linking prior shootings to charged murders	Expert ballistics linkage is relevant and admissible to prove means and identity; trial court properly limited scope	Ballistics methodology unreliable; testimony therefore irrelevant to identity (should preclude evidence)	Defendant waived Porter challenge by not requesting hearing; trial court did not abuse discretion — relevance is broad and expert testimony tended to prove identity
Prejudicial effect vs. probative value of uncharged‑misconduct evidence	Probative value high: only evidence tying defendant to murder weapon, temporal proximity, limiting instructions mitigated prejudice	Prior incidents were similarly themed and emotionally prejudicial; risk of propensity inference and jury distraction	Probative value outweighed prejudice given careful scope limits, excluded inflammatory details, temporal proximity, and repeated limiting instructions; admission upheld

State v. Porter, 241 Conn. 57 (Porter hearing requirement for scientific methodology)
State v. Raynor, 337 Conn. 527 (Porter hearing necessary where methodology challenged; science evolves)
State v. Collins, 299 Conn. 567 (broad relevancy for linking same‑gun prior acts to charged crime)
State v. Edwards, 325 Conn. 97 (Porter/Daubert framework and admissibility principles for scientific evidence)
State v. Turner, 334 Conn. 660 (failure to request Porter hearing waives methodological challenge)
State v. Beavers, 290 Conn. 386 (limiting admission by excluding most prejudicial details supports admissibility)