One Last Mail Exchange: The Murder of Amy Marie Derewitz
Amy Marie Derewitz told her mother she was going to her ex-boyfriend's house for one final mail exchange. It was Sunday, June 3, 2001, and the 22-year-old wanted to tie up the last loose ends from her failed relationship with David Kniga. They had been buying a house together, building what they thought would be a future. But that future had collapsed, and Amy had moved back home with her mother in Dearborn Heights, Michigan. She just needed to swap some remaining mail, handle a few final details, and then she would never have to see Kniga again.
Amy left her mother's house wearing a grey t-shirt, reddish colored boxer shorts, and house slippers. It was casual clothing, the kind you wear when you're running a quick errand and plan to be home soon. She drove her teal green 1994 or 1995 Ford Escort the short distance to the house she had once shared with Kniga, located at the corner of Detroit and Colgate Streets. The house was only blocks away from her mother's home. It should have been a ten-minute trip there and back.
Amy never came home. What happened inside that house on June 3, 2001, would remain officially unknown for more than two years. But witnesses would eventually paint a picture of a confrontation that turned deadly, of a new girlfriend who saw Amy gasping for breath on the basement floor and did nothing, of a man who told his girlfriend "I took care of it" when she asked where Amy had gone. David Kniga would eventually confess to killing Amy and claim he disposed of her body in a dumpster near the former Veterans Affairs Hospital in Allen Park, Michigan. Despite this confession, despite searches, despite the passage of more than two decades, Amy Marie Derewitz has never been found. Her killer served only ten years in prison before walking free, leaving Amy's family without closure, without justice, and without answers about where their daughter's body lies.
A Life Just Beginning
Amy Marie Derewitz was born around 1979, growing up in the Dearborn Heights area of Michigan. Standing 5'4" tall and weighing approximately 108 pounds, she had brown eyes and hair that friends described as dark blonde to light brown, long and thick. She had her ears and navel pierced, small personal touches that spoke to her youth and style. Those who knew Amy described her as extremely dependable, someone who would never simply leave without warning or explanation.
By 2001, Amy was working at Oakwood Commons in Dearborn as a receptionist and server, a job she had held since high school. The work was steady and she was good at it, known for her reliability and pleasant demeanor with customers. But Amy had bigger aspirations than working in food service forever. She had enrolled at Henry Ford Community College and was planning to change her studies from health-related fields to business classes. She was reassessing her future, figuring out what she really wanted from life, the way many people in their early twenties do.
Her personal life had recently undergone significant changes as well. Amy had been in a relationship with David Kniga, and the relationship had progressed to the point where they were purchasing a house together. Buying a home is a serious commitment, a statement that two people are planning to build a future together. For a young woman in her early twenties, it represented stability, adulthood, a step forward into the life she wanted to create.
But somewhere along the way, the relationship had fallen apart. The reasons for the breakup remain largely private, but by June 2001, Amy and Kniga were no longer together. Amy had moved back home with her mother, returning to the safety and support of her childhood home while she figured out her next steps. Kniga remained in the house they had been buying together. And in the way these situations often unfold, there were practical matters to settle: mail still arriving at the old address, belongings to be returned, financial details to finalize.
The Day She Vanished
On Sunday, June 3, 2001, Amy told her mother about her plans for the day. She needed to go to Kniga's house to exchange mail. Both of them were still receiving correspondence at the address where they had lived together, and it needed to be sorted out. Amy's mother would later tell investigators that Amy had characterized this visit as the last time she would have to see her ex-boyfriend. It was meant to be a final, closing interaction. After this, Amy could move forward with her life without any remaining ties to her past relationship.
The plan seemed straightforward and safe enough. It was the middle of the day. The house was in a residential neighborhood, close to Amy's mother's home. It was a quick errand. Amy didn't bother changing out of her casual house clothes. She slipped on a pair of house slippers and headed out the door, driving the short distance to the house on Detroit and Colgate Streets.
What Amy didn't know was that Kniga's new girlfriend, Jennifer St. John, would be at the house. Whether this was intentional or coincidental remains unclear, but the presence of another woman created a volatile situation. Amy and St. John had never met, or if they had, not under these circumstances. Amy was there for practical reasons, to handle the mundane business of redirecting mail. But emotions in these situations are rarely purely practical.
According to testimony that would later emerge at a court hearing, a confrontation occurred between Amy and Kniga. The exact nature of the confrontation, what was said, what sparked it, remains known only to those who were present. But at some point during this encounter, the situation escalated from a verbal dispute to physical violence. Kniga told St. John to leave the house. She complied with his request, walking out the door as instructed.
But before St. John left, she saw something that should have compelled her to call for help immediately. She observed Amy lying on the basement floor, gasping for breath. Amy was clearly in distress, struggling to breathe, possibly dying. St. John did nothing. She did not call 911. She did not summon an ambulance. She did not attempt to help Amy in any way. She simply left the house, leaving Amy alone with Kniga while Amy fought for her life on the basement floor.
When St. John returned to the house later, Amy was gone. St. John asked Kniga where Amy was, where the woman she had left gasping on the floor had gone. According to St. John's later testimony, Kniga's response was chilling in its brevity: "I took care of it."
The Search Begins
When Amy failed to return home that Sunday evening, her mother knew immediately that something was wrong. Amy was dependable. She had said she would be gone for a short time to handle the mail exchange. She should have been home hours ago. Her mother contacted authorities, reporting Amy missing. The investigation into Amy's disappearance began that same day.
Four days later, on June 7, 2001, Amy's teal green Ford Escort was discovered abandoned in the parking lot of Ten Eyck Park. The park was only two blocks away from Amy's mother's home, almost halfway between where her mother lived and the house Amy had shared with Kniga. The car had apparently been parked there on June 5 or 6, a day or two after Amy's disappearance. Investigators processed the vehicle, searching for fingerprints and other evidence. They found no readable fingerprints inside. Amy's personal belongings, including her purse and identification, were not in the car. They had vanished along with Amy herself.
The location of the abandoned car was significant. Someone had driven Amy's car from Kniga's house and left it at Ten Eyck Park, parking it in a public lot where it would eventually be noticed and reported. Was it Amy who parked the car there? That seemed unlikely given that she never returned home and was never seen again. Was it Kniga? If so, when did he drive it there, and how did he get back to his house? These questions would become part of the growing body of evidence that investigators were assembling.
Neighbors in Kniga's area began coming forward with information. One neighbor testified that she had seen Kniga leaving his house carrying what appeared to be a full laundry bag. The timing of this sighting coincided with the period when Amy was missing. A laundry bag large enough to hold clothing could also be large enough to hold a body, particularly the body of a young woman who weighed only 108 pounds. The neighbor's observation, combined with St. John's testimony about seeing Amy on the basement floor and Kniga's ominous statement about "taking care of it," began to paint a disturbing picture of what had happened.
The Investigation Unfolds
Despite the growing evidence that Amy had been murdered, investigators faced a significant challenge: there was no body. Without Amy's remains, proving that she was dead rather than simply missing required circumstantial evidence and witness testimony. The case would depend heavily on what Jennifer St. John was willing to say about what she had seen and heard.
St. John cooperated with law enforcement. She agreed to be interviewed. She provided her account of the events of June 3, 2001. Crucially, she agreed to take a polygraph examination regarding Amy's disappearance. She passed the polygraph, lending credibility to her version of events. Her testimony would become the cornerstone of the case against David Kniga.
Investigators asked Kniga to submit to a polygraph examination as well. Initially, he was scheduled to take the test. However, when the time came, Kniga changed his mind. Instead of taking the lie detector test, he hired an attorney. This decision, while legally prudent and within his rights, raised obvious questions about what he might be trying to hide.
Kniga maintained his innocence in Amy's disappearance. He admitted that both his new girlfriend and Amy had been at his home on June 3, but he claimed they had arrived at different times. This contradicted St. John's testimony about being present during a confrontation and seeing Amy on the floor. Kniga's story simply didn't align with the physical evidence or the witness accounts. But without a body, without forensic evidence of a murder, the case remained difficult to prosecute.
For more than two years, Amy's case remained in this frustrating state of limbo. Her family knew she was likely dead. Investigators believed they knew who had killed her. But building a murder case without a body is always challenging. Prosecutors needed to be confident that they had sufficient evidence to convince a jury that Amy was dead and that David Kniga had killed her. They continued to investigate, to build their case, to wait for the right moment to move forward with charges.
Justice, Of A Sort
In June 2003, more than two years after Amy vanished, authorities finally charged David Kniga with second-degree murder in her case. At the time of his arrest, Kniga was still living in the home he had once shared with Amy, the house where she had gone for that final mail exchange and never left alive. A Dearborn Heights district judge ruled there was sufficient evidence to try Kniga on the murder charges despite the absence of a body.
Initially, Kniga pleaded not guilty to the charge. He maintained that he had not killed Amy, that he did not know where she was. The case moved toward trial, with prosecutors preparing to present their circumstantial evidence: St. John's eyewitness testimony about seeing Amy on the basement floor, the neighbor's account of seeing Kniga with the large laundry bag, Kniga's statement about "taking care of it," the abandoned car, Amy's complete disappearance without any activity on her bank accounts or credit cards.
Then, in October 2003, Kniga changed his plea. Rather than face trial on second-degree murder charges that could result in a life sentence if he was convicted, he pleaded guilty to the lesser charge of manslaughter. The plea deal represented a compromise that allowed prosecutors to secure a conviction without the uncertainty of a trial, while giving Kniga a much lighter sentence than he would face if convicted of murder.
As part of the plea agreement, Kniga made a statement about what he had done with Amy's body. He claimed that after killing her in the basement of their shared home, he put her body in a dumpster near the former Veterans Affairs Hospital in Allen Park, Michigan. This was the first time Kniga had publicly acknowledged killing Amy. It was a confession, but one that came with minimal consequences.
Kniga was sentenced to five to fifteen years in prison for manslaughter. Given that he could have faced life imprisonment if convicted of murder, this was an extraordinarily lenient sentence for taking someone's life. The plea deal meant that Kniga would be eligible for parole after serving just five years, a third of the maximum sentence. For Amy's family, the plea deal was a bitter pill to swallow. Their daughter's killer had confessed, but he would spend less time in prison than Amy had been alive.
The Missing Remain Missing
Kniga's confession about disposing of Amy's body in a dumpster near the VA hospital should have provided closure of a sort. Her family could at least know what had happened to her remains, even if they couldn't recover them. Dumpsters are emptied into garbage trucks, which compress and crush their contents before depositing everything in landfills. If Kniga had indeed put Amy's body in a dumpster in June 2001, her remains would have been transported to a landfill somewhere in the area, buried under tons of garbage. Finding human remains in such circumstances is nearly impossible.
However, even this grim form of closure remains uncertain. Kniga's claim about the dumpster location was never verified. No evidence was found to confirm his story. He may have been telling the truth about using a dumpster to dispose of Amy's body. Or he may have been lying, providing false information as part of his plea deal while keeping the true location of Amy's remains secret. Without independent verification, without any physical evidence to support his claim, investigators and Amy's family have no way of knowing whether Kniga told the truth about what he did with her body.
Searches were conducted in the area Kniga indicated, but they yielded no results. The VA hospital location he mentioned provided no clues. Amy's body was not found. Her remains were not recovered. She is still, officially, a missing person, even though her killer confessed to murdering her more than twenty years ago.
In 2015, after serving approximately ten years in prison, David Kniga was paroled. He had served two-thirds of the maximum sentence under his plea deal, enough time to qualify for release under Michigan's parole guidelines. In 2017, he was discharged from parole, meaning he had completed all requirements of his sentence and was free from any further supervision by the criminal justice system. The man who killed Amy Marie Derewitz, who left her dying on a basement floor, who disposed of her body in a manner that has prevented her family from ever burying her, walked free after serving just ten years.
A Family Without Closure
For Amy's family, the years since 2001 have been marked by a grief complicated by the absence of remains and by the inadequacy of the justice system's response. They know their daughter is dead. They know who killed her. They even know, roughly, when and where she died. But they don't know where her body is. They have no grave to visit. They have no place to bring flowers on her birthday or on the anniversary of her death. Amy exists in a painful limbo, legally dead but physically unfound.
The family offered a $5,000 reward for information leading to Amy's whereabouts, hoping that someone might come forward with details about where her body might be. The reward remains unclaimed. No credible tips have emerged that would lead to the recovery of her remains. The investigation into her disappearance remains technically open, though there is little active work being done on a case where the perpetrator has already been convicted and served his sentence.
Amy's mother has had to live with the knowledge that her daughter's killer served only a decade in prison for taking Amy's life. The plea deal that secured Kniga's conviction also ensured he would face minimal consequences for his crime. The criminal justice system valued the certainty of a conviction over the severity of punishment, a calculus that makes sense from a prosecutorial standpoint but offers little comfort to a grieving mother.
The case also raises disturbing questions about Jennifer St. John's actions on June 3, 2001. She saw Amy lying on the basement floor, gasping for breath, clearly in medical distress. She did nothing to help. She did not call 911. She did not attempt CPR or first aid. She simply left, following Kniga's instruction to leave the house. Her inaction may have cost Amy her life. If St. John had called for help immediately, paramedics might have arrived in time to save Amy. Even if Amy was already beyond saving, St. John's prompt call to emergency services might have resulted in Kniga's immediate arrest, preventing him from disposing of Amy's body.
Yet St. John faced no charges for her failure to act. Michigan law, like the law in most states, generally does not impose a duty to rescue strangers or to summon help for someone in distress. There are exceptions for people with special relationships to the victim, like parents and children, but a romantic rival does not fall into this category. St. John was not legally required to help Amy, even though morally and ethically, most people would agree she should have. Her willingness to later testify against Kniga may have played a role in prosecutors' decision not to pursue charges against her for her inaction on the day Amy died.
Where Is Amy?
More than twenty-three years after her disappearance, the question remains: where is Amy Marie Derewitz? If Kniga told the truth about disposing of her body in a dumpster, her remains are likely in a landfill somewhere in southeastern Michigan, buried under years of accumulated garbage. Landfills are vast spaces that receive tons of waste daily. Finding human remains in a landfill, especially remains that have been there for decades, is nearly impossible without extremely specific information about location and depth.
However, Kniga had every reason to lie about the location of Amy's body. By providing a story that led to a landfill, an essentially unsearchable location, he gave investigators and Amy's family just enough information to satisfy the terms of his plea deal while ensuring that Amy would never actually be found. If he had disposed of her body in a location where it might be recovered, there would be physical evidence of the crime. There might be forensic details about how she died that would contradict his account or reveal the full extent of his actions. By claiming he put her in a dumpster, Kniga eliminated any possibility of such evidence coming to light.
It's also possible that Kniga disposed of Amy's body somewhere else entirely. He had access to a vehicle. He had several days before Amy's car was found, several days before investigators focused their attention on him. He could have driven to a remote location, to a body of water, to a wooded area, to any number of places where a body might remain hidden for years or forever. Without witnesses to what he did after St. John left the house, without forensic evidence, the truth about what happened to Amy's remains may be known only to David Kniga.
A Life Interrupted
Amy Marie Derewitz would be approximately 45 years old today if she had lived. She would have completed her business studies at Henry Ford Community College. She would have pursued the career she was planning, built the life she dreamed of, moved past the failed relationship with Kniga and found happiness with someone who valued and respected her. She would have had the opportunity to grow older, to achieve her goals, to experience everything that life might have offered her.
Instead, her life ended at 22, on the basement floor of a house she had once called home, killed by a man she had once trusted enough to buy a house with. Her body was disposed of like trash, tossed away and lost. Her family was robbed of the chance to say goodbye, to hold a funeral, to have a place where they could go to feel close to her.
The circumstances of Amy's death highlight a tragedy that occurs far too often: intimate partner violence that turns deadly. Amy and Kniga were no longer together, but the violence that killed her occurred in the context of their past relationship. The confrontation on June 3 was about the remnants of their shared life, about mail and practical matters, about the difficulty of fully separating from someone you once planned a future with. For reasons that may never fully be understood, that confrontation turned violent, and Amy paid with her life.
The Unsatisfying End
David Kniga is free today. He served his sentence, completed his parole, and was discharged from supervision in 2017. He can go where he wants, do what he wants, live his life without restriction. Meanwhile, Amy remains missing, her body never recovered, her family never able to properly lay her to rest.
The case of Amy Marie Derewitz is officially solved in that her killer has been identified, prosecuted, and convicted. But in every meaningful sense, it remains tragically incomplete. Amy has not been found. Her family has not received the closure that comes with recovering a loved one's remains. Justice, such as it was, consisted of a manslaughter conviction and a ten-year prison sentence for a murder that destroyed a young woman's life and devastated a family.
Amy's story is a reminder that legal justice and true justice are not always the same thing. The system can identify a perpetrator, secure a conviction, and impose a sentence, and still leave victims' families feeling that justice has not been served. Amy deserved better than to die on a basement floor at 22. She deserved better than to be disposed of in a dumpster or wherever Kniga actually put her body. She deserved better than a plea deal that let her killer walk free after just a decade. But the justice system, with all its limitations and compromises, gave her no more than this.
If David Kniga reads these words, if he reflects on what he did, perhaps there is still an opportunity for him to do one decent thing. He could tell Amy's family the truth about where their daughter's body is. He could give them the chance to bring her home, to finally bury her with dignity and love. It would not undo the murder. It would not restore the years Amy should have lived. But it would provide a small measure of peace to a family that has lived with uncertainty and pain for more than two decades. Amy Marie Derewitz deserves to be found. Her family deserves to know where she is. And somewhere, in David Kniga's conscience, there may still be enough humanity left to give them that final gift.
Sources
- The Charley Project: Amy Marie Derewitz
- The Doe Network: Amy Marie Derewitz
- NamUs: Missing Person Case MP8834
- UPI: Murder trial on despite no body
- Crime Net: Rewards - Missing Persons and Unsolved Crimes
- Crime in Detroit: Missing - Amy Marie Derewitz
