State v. M. Blaz, 388 Mont. 105

On August 16, 2013, 53‑day‑old Matti died while in Matthew Blaz’s care; autopsy found craniocerebral and cervical trauma and retinal hemorrhages; Medical Examiner ruled the manner homicide.
Blaz had previously (July 10, 2013) pled guilty to Partner or Family Member Assault (PFMA) for violently assaulting Jennifer (Matti’s mother) in the same home; that incident involved grabbing and slamming Jennifer’s head against the floor.
Blaz’s trial defense was that a neighbor boy accidentally dropped Matti, causing her fatal injuries.
The State sought to admit evidence of the earlier PFMA under M. R. Evid. 404(b) to prove motive, identity/pattern (modus operandi), and absence of accident; the District Court admitted it and gave a limiting instruction.
Blaz was convicted of Deliberate Homicide; on appeal he challenged (1) admission of the PFMA evidence under Rule 404(b)/403 and (2) that the written judgment omitted 318 days’ credit for time served (which was orally pronounced).

Issue	Plaintiff's Argument (State)	Defendant's Argument (Blaz)	Held
Whether admission of prior PFMA was improper under M. R. Evid. 404(b) / 403	PFMA shows motive (hostility toward mother/children), identity/pattern (similar mechanics: head slammed against broad surface, private home, female family victims), and rebuts accidental‑drop defense	PFMA is propensity evidence; not sufficiently distinctive to be modus operandi; not necessary to rebut accident because nonaccidental trauma was undisputed; unfairly prejudicial	Court affirmed admission: PFMA admissible for motive, identity/pattern, and absence of accident; limiting instruction and Rule 403 balancing cured unfair prejudice.
Whether the written judgment’s omission of 318 days’ credit was error	— (the State conceded credit was due)	Blaz argued written judgment failed to reflect orally pronounced credit for 318 days served	Court reversed in part and remanded: judgment must be amended to credit Blaz with 318 days time served.

State v. Daffin, 387 Mont. 154, 392 P.3d 150 (discussing Rule 404(b) admissibility and ‘criminal signature’/pattern evidence)
State v. Madplume, 386 Mont. 368, 390 P.3d 142 (admitting similar‑acts evidence to show plan/sequence of conduct)
State v. Dist. Court of the Eighteen Judicial Dist. (Salvagni), 358 Mont. 325, 246 P.3d 415 (limitations on 404(b); use to rebut accident and show motive)
State v. Aakre, 309 Mont. 403, 46 P.3d 648 (404(b) evidence must be clearly justified and limited)
State v. Sweeney, 299 Mont. 111, 999 P.2d 296 (greater distinctiveness required to use other‑acts evidence to prove identity)
State v. Kordonowy, 251 Mont. 44, 823 P.2d 854 (identity exception where modus operandi is earmark of accused)
State v. Stewart, 367 Mont. 503, 291 P.3d 1187 (discussion of elements and role of other‑acts evidence in proving actus reus/intent)
State v. Hantz, 372 Mont. 281, 311 P.3d 800 (limiting instructions can cure prejudice from other‑acts evidence)
State v. Hicks, 369 Mont. 165, 296 P.3d 1149 (definition of unfair prejudice under Rule 403)