## Facts

- Johannes Mehserle, a Bay Area Rapid Transit (BART) police officer, responded to a reported fight on a BART train shortly after 2:00 a.m. on January 1, 2009.
- On the Fruitvale station platform in Oakland, California, Mehserle confronted Oscar Grant during an arrest attempt.
- Grant was lying face down on the platform and was unarmed.
- Mehserle shot Grant in the back, killing him.
- Mehserle asserted he intended to deploy his Taser but accidentally drew and fired his handgun.
- Evidence at trial addressed differences between the Taser and handgun (including placement on the body and operational features) and the circumstances surrounding Mehserle’s draw and firing.
- A jury acquitted Mehserle of murder and voluntary manslaughter but convicted him of involuntary manslaughter, necessarily finding the shooting was not purely accidental but criminally negligent.
- The trial court sentenced Mehserle to two years in prison and denied probation.

## Issues

1. Whether substantial evidence supported the jury’s finding of criminal negligence required for involuntary manslaughter.
2. Whether the trial court prejudicially erred in instructing the jury on involuntary manslaughter and criminal negligence.
3. Whether the trial court abused its discretion in denying a new trial based on alleged newly discovered evidence related to weapon confusion and training.
4. Whether the trial court erred by excluding evidence of BART’s post-incident Taser policy changes and whether exclusion violated the right to present a defense.
5. Whether the trial court abused its discretion in denying probation and in sentencing.

## Decision

- The Court of Appeal affirmed the judgment of conviction and sentence.
- The court held substantial evidence supported the involuntary manslaughter verdict based on criminal negligence.
- The court rejected an occupation-specific criminal-negligence standard and applied the objective reasonable-person standard.
- The court found no prejudicial instructional error when the instructions were considered as a whole.
- The court upheld exclusion of BART’s post-incident Taser policy changes under Evidence Code § 352 and found no constitutional violation.
- The court affirmed denial of a new trial motion and found no abuse of discretion in denying probation.

## Legal Principles

- Involuntary manslaughter includes a killing committed during a lawful act performed “without due caution and circumspection,” requiring proof of criminal negligence.
- Criminal negligence is evaluated objectively and requires a gross departure from the conduct of an ordinarily prudent person, creating a high risk of death or great bodily injury.
- California criminal negligence doctrine does not create a separate “reasonable police officer” standard or heightened “wantonness” requirement for law enforcement defendants.
- On substantial-evidence review, an appellate court views evidence in the light most favorable to the judgment and does not reweigh credibility.
- Evidence may be excluded under Evidence Code § 352 when limited probative value is substantially outweighed by risks of confusion, undue consumption of time, or a distracting collateral inquiry; excluding marginal defense evidence does not necessarily violate the right to present a defense.
- A new trial based on newly discovered evidence is discretionary and may be denied when the evidence is cumulative, insufficiently material, or unlikely to change the result.
- Probation and sentencing decisions are reviewed for abuse of discretion.

## Conclusion

The court upheld Mehserle’s involuntary manslaughter conviction, ruling that the jury could reasonably find criminal negligence from his drawing and firing a handgun against an unarmed, prone suspect, and confirming that California applies an objective reasonable-person standard to criminal negligence claims by on-duty police officers while permitting exclusion of marginal post-incident policy evidence under Evidence Code § 352.


People v. Mehserle, 206 Cal. App. 4th 1125 (Cal. Ct. App. 2012)