## Facts

- Dr. Hsiu Ying “Lisa” Tseng, a licensed physician, practiced at a clinic that shifted from a conventional practice to a high-volume, cash-based operation known for easy access to controlled-substance prescriptions.
- Tseng often spent only minutes per patient, sometimes saw multiple patients in the same exam room, and frequently did not obtain prior medical records or conduct meaningful physical examinations.
- She regularly prescribed large quantities and high doses of controlled substances, including opioids, benzodiazepines, and muscle relaxants, and issued dangerous combinations without legitimate medical justification.
- Tseng recognized many patients were drug-seeking or addicted, yet continued prescribing in the same manner.
- Multiple patients died from overdoses shortly after receiving prescriptions from Tseng; three deaths were charged as second-degree murder, and six additional overdose deaths were introduced as uncharged-acts evidence.
- A jury convicted Tseng of three counts of second-degree murder, nineteen counts of unlawfully prescribing controlled substances, and one count of obtaining a controlled substance by fraud; she received an aggregate sentence of 30 years to life.

## Issues

1. Whether substantial evidence supported the three second-degree murder convictions on an implied-malice theory based on Tseng’s prescribing practices.
2. Whether Tseng’s prescriptions were a proximate cause of the three charged overdose deaths despite other substances and the patients’ voluntary ingestion.
3. Whether admitting evidence of six uncharged overdose deaths was an abuse of discretion or violated due process.
4. Whether the trial court erred in refusing to unseal and quash a search warrant for Tseng’s financial records.
5. Whether alleged prosecutorial misconduct, reopening of closing argument, or sentencing rulings (including refusal to apply Penal Code § 654 to the murder terms) required reversal.

## Decision

- The Court of Appeal affirmed the judgment in full.
- Substantial evidence supported implied malice because Tseng intentionally prescribed high-dose and high-risk drug combinations without legitimate medical reasons, knew such conduct endangered life, and persisted despite repeated warnings and overdose information.
- The evidence supported causation because expert medical and toxicology testimony showed the prescribed drugs were a substantial factor in each death, and intervening conduct was foreseeable given Tseng’s awareness of patient drug abuse.
- The trial court properly admitted evidence of six uncharged overdose deaths for non-propensity purposes (including knowledge and absence of mistake), and the probative value was not substantially outweighed by unfair prejudice.
- The court found no reversible error regarding the financial-records warrant, claimed prosecutorial misconduct, the limited reopening of closing arguments, or sentencing, including the refusal to stay murder sentences under Penal Code § 654.

## Legal Principles

- Implied-malice second-degree murder requires an intentional act, the natural consequences of which are dangerous to human life, performed with subjective awareness of the danger and conscious disregard for human life.
- A physician’s training and experience may support an inference of subjective awareness of overdose risks from prescribing high-dose opioids and dangerous drug combinations without medical necessity.
- Proximate causation is satisfied when the defendant’s conduct is a substantial factor in the death; foreseeable intervening acts (including voluntary ingestion and polypharmacy by drug-seeking patients) do not break the causal chain.
- Evidence of other overdose deaths linked to the same prescribing practices may be admissible to prove knowledge, intent, and absence of accident, subject to standard prejudice-balancing limits.
- Appellate reversal for prosecutorial misconduct or trial-management decisions requires a showing of prejudicial error affecting the verdict; sentencing stays under Penal Code § 654 are not required when convictions reflect distinct harms and objectives.

## Conclusion

The court upheld convictions and a 30-years-to-life sentence, holding that a physician who knowingly and unjustifiably prescribes lethal drug combinations in the face of clear overdose risks may be found to have acted with implied malice, and that foreseeable patient misuse does not defeat causation for overdose deaths.


People v. Tseng, 30 Cal. App. 5th 117, 241 Cal. Rptr. 3d 194 (Cal. Ct. App. 2018)