Overview
- Jurors found the killing of Marina Placensia to be an act of domestic violence, and Mantych faces life without parole with sentencing set for Jan. 9, 2026.
- Prosecutors said Mantych smothered Placensia in her seat overnight before the train reached Denver as she sought to leave the relationship with her children.
- Outside expert Bill Smock concluded in 2023 that injuries to Placensia’s mouth were consistent with suffocation, leading to Mantych’s arrest and charge.
- Investigators reported bruising and other signs of a struggle and recorded Mantych giving conflicting accounts of where he sat on the train.
- The defense cited possible natural causes and investigative delays, but the jury returned a guilty verdict after about five hours of deliberation.