It took nine years for the boyfriend of a 28-year-old woman who died during an overnight Amtrak trip to be tried for her murder, but on Monday an expert witness testified that Marina Placensia had indisputably been suffocated.
“Ms. Placensia was suffocated to death,” Dr. Bill Smock, a nationally known expert in asphyxia deaths, testified at the trial of 43-year-old Angelo Mantych, who’s charged with first-degree murder, The Denver Post reported. “She died because she couldn’t breathe. Period. This is homicide. Death at the hands of someone else. Literally the hands of someone else.”
Mantych, Placensia and their four children had boarded an Amtrak train in Wisconsin on Aug. 30, 2016, bound for Denver, where the family planned to relocate. When it pulled into Denver’s Union Square Station, Placensia was dead in her seat.
Mantych told police he’d found his “heavy sleeper” of a partner unresponsive when he twice tried to wake her before arrival, according to a 2023 affidavit released by the Denver District Attorney’s Office.
She was slumped over in her seat, still warm and not stiff, but not breathing, with her bra shoved up above her breasts, an assistant conductor who tried to revive her testified. She was also covered in bruises, and an autopsy revealed 35 injuries ranging from contusions to broken ribs and internal bleeding.
The injuries correlated with the physical and mental abuse her family and friends said Mantych inflicted both on Placensia and the four kids, three of whom the couple shared.
She was finally ready to leave the situation, her brother told Denver’s Fox affiliate KDVR, and family members were on hand to pick up Placensia and the children and tell Mantych to take a hike. But he’d gotten wind of the plan and told Placensia that “he would kill her if she left with the children,” according to the affidavit.
However, the Denver Office of the Medical Examiner could not determine a cause of death, and the case went cold until Smock was called in. The strangulation and suffocation expert with the Louisville, Kentucky, Metro Police Department, who also testified in the George Floyd Case, discerned telltale signs.
The awkward bra position indicated struggle, and a tooth imprint on Placensia’s lower lip showed how forcefully they’d been pressed together as she was suffocated, Smock told the court. Her gums bled during the 90 seconds that elapsed between air supply cutoff and loss of consciousness, during which Placensia was unable to scream or speak.
Her family is glad to see Mantych held to account.
“She was a hardworking woman. She did what she could to provide for her kids,” Placencia’s brother, Christopher Medina, told NBC affiliate KUSA. “I did everything I could for my sister. She was my best friend.”
