Marco Allen Chapman was born on September 4, 1971, in West Virginia. He had a difficult childhood. His parents struggled with alcoholism, which made things tough at home. Chapman faced severe abuse. His father not only abused alcohol but also sexually abused him and beat him to the point where he would become unconscious. His mother also hit him frequently, sometimes with a skillet. This environment led Chapman to feel suicidal as a child, pushing him toward drug abuse.

As Chapman's mental health deteriorated, he suffered from depression, flashbacks, and hallucinations. A court document later indicated that he showed signs of bipolar disorder. He dropped out of school in the 8th grade, leaving formal education behind.

Chapman eventually got into trouble with the law. He was convicted of bank robbery in Texas and went to prison. While serving his sentence at FCI Oakdale in Louisiana, he was known by the nickname "the kid." There, he worked in the paint shop and earned 19 cents an hour. Despite his past, Chapman was seen as a responsible worker and well-liked by other inmates. For the most part, he followed prison rules and avoided trouble.

After prison, he worked in construction and even served as a soccer coach. His last known address was in Warsaw, Kentucky, though he had also been staying at a home in Boone County.

On August 23, 2002, Marco Allen Chapman arrived at Carolyn Marksberry’s home in Warsaw, Kentucky, during the early morning hours. He knocked on her door and asked to use the telephone. Carolyn, who was awake, let him in. Chapman had previously spent time with Carolyn's family, even assisting with home repairs.

Once inside, Chapman attacked Carolyn, punching her in the stomach and pulling out a knife. He demanded money, and she gave him her credit cards and about $120 in cash. After binding her hands with duct tape and tying her to the bed frame, he raped her. He then proceeded to stab her multiple times, breaking two knives in the process. In total, he stabbed Carolyn more than 15 times before turning his attention to her children.

Their six-year-old son, Cody, was awakened by the commotion. He went to his mother but was told to return to bed. Instead, he woke his ten-year-old sister, Courtney. When they encountered Chapman in the hallway, he falsely told them that their mother needed an ambulance. He then attacked Courtney, slicing her ear; she fell to the floor and played dead. In the following moments, Courtney watched as Chapman stabbed Cody and then went into the bedroom of their seven-year-old sister, Chelbi. Chelbi fought back but was quickly killed as well.

As Chapman left the house, he took items with him and then fled the scene. Meanwhile, Carolyn, bleeding severely and still bound, managed to free herself after gnawing through her restraints. She crawled past Cody’s body to seek help from a neighbor.

Emergency responders arrived shortly after receiving a call. Carolyn and Courtney were taken to a hospital for treatment. Carolyn’s injuries were critical, and she underwent surgery for multiple stab wounds and a collapsed lung.

Later that day, Chapman was arrested in West Virginia. Police found blood on his clothes and a bloody knife in the vehicle he was driving. He confessed to the crimes during his arrest.

Chapman faced multiple charges, including two counts of murder and other offenses. His trial began after significant legal discussions regarding his mental state. During the proceedings, he showed little remorse, and at times appeared to joke about the gravity of his actions. Eventually, he changed his plea to guilty and requested the death penalty.

In December 2004, Chapman was sentenced to death without a jury trial for the murders of Cody and Chelbi. His appeals were consistently halted as he requested to waive them, stating he wanted his execution to relieve the suffering he caused.

On November 21, 2008, Chapman was executed by lethal injection. In his final moments, he expressed sorrow for his actions and the pain he caused the Marksberry family. After his execution, news outlets reported that Carolyn Marksberry commented on the importance of remembering the victims rather than focusing on Chapman.