We report a case of a 75-year-old hypertensive, diabetic man who presented to the emergency room with symptoms and signs of nausea, acute intoxication, significant alteration in mental status with rapid neurologic deterioration, and blunt impact injuries sustained during a recent altercation with a 36-year-old female companion-caretaker. He denied a history of ethanol abuse or other recent toxic ingestion and had not been diagnosed with or treated for depression. Hospital laboratory tests revealed a metabolic acidosis and a negative urine toxicology screen. He was diagnosed with toxic encephalopathy with metabolic acidosis secondary to metformin. Despite treatments including hemodialysis, he expired after approximately 28 hours of hospitalization. A postmortem anatomic examination revealed recent blunt-impact injuries and cardiac and renal pathology. A subsequent histologic examination revealed the presence of calcium oxalate crystals in the kidneys and brain, in addition to cardiac and renal pathology. Comprehensive forensic toxicologic testing was performed on antemortem and postmortem samples and revealed lethal levels of ethylene glycol. The cause of death was as a result of acute intoxication by ethylene glycol with another condition of multiple blunt impacts to the head, trunk, and extremities. The manner of death was ruled as homicide. A trial by jury, involving the female companion-caretaker, resulted in her conviction, and she was sentenced to 23 years to life in prison. In this report, we present an unusual case of homicidal ethylene glycol intoxication in which legal proceedings have occurred.