Editor's note: This story contains descriptions of domestic violence that may be disturbing to some readers.
One Denver family believes justice has finally been served for their loved one, almost a decade after she was murdered while trying to escape an abusive relationship.
The case highlights the complexities of domestic violence and shines a light on the nuances that require a deeper understanding of the crime.
Marina Placensia was a beloved mother, sister, and daughter. Her family called Denver home, and she had four young children when her life was cut short at 28.
“My sister was always full of joy, full of energy,” said her older brother, Christopher Medina, whose eyes lit up while talking about his sister. "She was a very adventurous individual, and she loved everybody.”
Medina knew Placensia’s partner, Angelo Mantych, who fathered three of her children.
“It was like any other relationship," Medina explained. "The first couple of years were great, you know what I mean? The kids came along, things were going great, and then the drinking started, and then the abuse.”
Medina said he attempted multiple times to help Placensia leave Mantych. He stated the family crafted a plan to help her escape the abuse in 2016.
On Aug. 31, 2016, Placensia and her children boarded an Amtrak train bound for Colorado from Wisconsin. Placensia and her family were living in Wisconsin at the time.
“She wanted to get away, and we finally got it to where she could come home,” Medina said. "We were going to meet as a family up there — my mother, myself, my wife — and we were going to gather her and the kids and just go. Leave him there.”
The train arrived at Denver’s Union Station the morning of September 1, 2016. Placensia was found dead.
“At the time, I lived fairly close to Union Station, so I was able to get down there very quickly. When I got there, my sister was already gone," Medina said. “It was, it was heartbreaking.”
Mantych was charged with Placensia’s murder seven years after her death on the train at Union Station. His arrest warrant details chilling accounts of an abusive relationship that ended in Placensia’s death.
Within Mantych’s arrest warrant, one friend of Placensia’s told law enforcement she was present for a phone call between Placensia and her family. Mantych allegedly had Placensia take the call on speaker phone, and the family discussed their plans to “get her away from Angelo and back to Colorado.” The friend said Mantych heard that conversation and told Placensia, “he would kill her if she left with the children.”
The documents claim Placensia was discovered on the train with a “large number” of bruises on her body, but none that investigators believed “would be an obvious cause of death.” Her bra was “up over her breasts” when a conductor went to help after being alerted to an unresponsive passenger.
According to the arrest warrant, Mantych tried to explain the bruises by saying Placensia was “banged up from moving.”
Mantych also told investigators he tried to wake Placensia roughly 20 minutes before the train arrived in Denver, but she was a “heavy sleeper.”
The arrest warrant includes accounts from several different people who told law enforcement they either witnessed or heard the abuse inflicted upon Placensia, in addition to a description of a 2015 police report out of Wisconsin, where Mantych was charged with assault after punching Placensia on the side of her head. The documents state that after the alleged assault, Placensia could not hear out of her left ear.
Originally, Placensia’s autopsy report listed her cause and manner of death as undetermined.
In 2022, an expert on strangulation and suffocation reviewed Placensia’s case to help determine her cause and manner of death. In 2023, the doctor told investigators he believed Placensia’s cause of death was suffocation, and her manner of death was homicide.
After years of investigation and expert review, this year, Mantych’s homicide case was taken to trial by the Denver District Attorney’s Office.
“It just required a lot of investigation and kind of commitment to keep looking at what happened,” said Assistant District Attorney Lara Mullin, when asked about the length of time between the crime and the trial. "And obviously, you know, the medical side of this is still catching up in terms of identification of smothering. And so, once that piece was in place, we were able to go forward.”
On Friday, prosecutors secured a guilty verdict from the jury in Mantych’s trial.
Her brother Medina was listening to the livestream when the verdict was announced, while picking up his son from school.
“When I heard guilty, I literally started just smacking my steering wheel, honking the horn. My son gave me a weird look like, ‘What’s wrong, Dad?’ And I told him, ‘They got him, baby, they finally got him,’" Medina recounted to Denver7.
Medina said justice was served for his sister when Mantych was convicted of first-degree murder.
“Sis, we did it," Medina said, looking at the sky. “They finally got him, and now you can finally have justice, and you can have peace.”
Despite a decrease in overall homicides across the state last year, domestic violence deaths increased by nearly a quarter in 2024. However, findings from the Colorado Domestic Violence Fatality Review Board highlight an even more alarming trend: all collateral domestic violence deaths last year were children between 3 months and 7 years old. In fact, kids have made up more than half of all collateral deaths over the past four years.
In Denver, the Rose Andom Center provides those living in abusive relationships with access to multiple services at one location. Meanwhile, Natasha Adler, the program director at the Rose Andom Center, also offers expert witness testimony in trials related to domestic violence.
Adler, who did not testify in Mantych’s trial but followed it closely, explained the dangerous dynamics she believes were present in Mantych and Placensia’s relationship.
First, Adler explained how power and control play a role in domestic violence by using an example of two people taking up space inside one room.
“If we’re in a healthy relationship, I take up a certain amount of space. You take up a certain amount of space. We have equal space,” Adler said. "If I’m trying to be an abusive partner, I need to take up more space to be able to dominate, to control, to manipulate, to whatever. The only way that I can take up more space in that room, though, because there’s only so much space, is to make you smaller. How am I going to do that? I’m going to put you down, I’m going to make you feel scared. I’m going to take away your resources. I’m going to isolate you. I’m going to use all of these different abusive tactics to make you feel small so I can take up more space in the relationship. Then I have the power, and I’m able to control the dynamic and the situation, because now you have lost all these things that give you power and control, and not in a bad way, but you know, the autonomy that you would inherently have as a person in a healthy relationship. Now I own that.”
Adler considers domestic violence to be a public health issue, and said a deep understanding of the complexities connected to abusive relationships can help someone identify signs of a loved one who may be struggling.
“To recognize those signs is extremely important to homicide prevention and just general awareness, but also to educate the public and educate other folks about domestic violence in the community, because it really does touch everybody," Adler said.
There are many misconceptions about a person “staying” in an abusive relationship, according to Adler.
“If you’ve been in an abusive relationship and you haven’t had access to those tangible things — like transportation, finances, a safe place to stay — those can be really big barriers to overcome,” Adler explained. “There are also those emotional barriers, too. Wanting to keep the family together, right? If you share children, you want to be able to keep that family unit alive, make sure that the children have access to the other parent, ensure that they are protected from other traumas.”
Adler said fear is another common tactic used by perpetrators of domestic violence, adding that the most dangerous time for a victim is when they leave an abusive relationship.
“It’s usually right within those first 30 to 90 days after leaving a domestic violence relationship. However, it can be really any time where there’s that loss of power and control,” said Adler. “Even just perceived loss [of power] can really shake the foundation of their control in the relationship, meaning that their tactics of abuse may not work anymore, and that can trigger that high lethality.”
In Mantych’s case, Adler believes he felt he was losing power and control over Placensia.
“I feel that the loss of control had been building for a long time,” Adler said about Mantych’s case. “The more that those people talked about the abuse, the more that it came to light, the more that his victim fought back and challenged him. All of those are challenges to that power and control dynamic, and I imagine that he did feel that loss.”
Placensia’s murder also illustrates how problematic strangulation can be, because in many cases, there are no external signs of injury.
“A lot of strangulation cases do not show outward signs of violence, so bruises don’t always show up. There’s not always broken bones. Additionally, with strangulation cases, a lot of the injuries are on the offender, and so they can be really difficult to prosecute, because there are defensive wounds,” said Adler.
While Adler admitted that defense attorneys have a job to do, she took issue with an argument used within Mantych’s trial, where his legal team alleged Placensia’s death was connected to substance use.
“It’s really dangerous to continue to lean into this narrative of substances or mental health being a part of somebody’s victimization and ultimate death because it increases the stigma of why we shouldn’t believe survivors,” said Adler. “There’s already this large narrative of why we shouldn’t believe survivors, that abusive partners continue to perpetuate. If we as society, as communities, as jurors, as friends, family — if we’re continuing to perpetuate that, that can be really dangerous for survivors to not only leave, but to come forward and to get verdicts like the one in the Mantych case.”
The murder of his sister changed the course of Medina’s life, but he is hopeful the resolution of Mantych’s case will bring some kind of closure.
“I lost my best friend,” Medina said about his sister. "I became really bitter, really angry, and now that I know he’s incarcerated, it’s going to take me time to change, but I will be able to change again.”
Mantych’s sentencing is scheduled for Jan. 9. In Colorado, a first-degree murder conviction carries a mandatory sentence of life in prison without the possibility of parole.
The sentencing hearing is when Placensia’s family can share victim impact statements with the court, explaining how this case has impacted their lives.
“That’s going to be one of the hardest things," Medina said about preparing his victim impact statement. “But it’s going to be a lot easier when I actually do get to say my statement right in front of him, and he can hear and feel my pain.”
If you or someone you know is experiencing domestic violence, help is available through Violence Free Colorado or the National Domestic Violence Hotline at 800-799-7233.
