Harry Edward Greenwell was born on December 9, 1944, in Louisville, Kentucky. He was the son of Paul and Dorothy Greenwell. In his early life, Greenwell faced legal troubles. On January 17, 1963, he was arrested for armed robbery in Louisville. He was sentenced on April 12, 1963, to two years in a reformatory and five years of probation. A few years later, on February 23, 1965, he was arrested again in Jefferson County, Kentucky, this time on a sodomy charge. He was paroled from the Kentucky State Penitentiary in 1969.

On April 28, 1978, tragedy struck when Greenwell's wife died in a house fire in Vernon County, Wisconsin. After this event, he met a 39-year-old single mother who had been in an abusive relationship. They eventually married, and Greenwell raised a daughter he had adopted from a previous marriage. He also fathered a son with his new wife.

In 1982, Greenwell faced more legal issues when he was arrested for burglary in Iowa. During his arrest, he managed to escape from custody but was recaptured twice. He served time in Anamosa State Penitentiary and the Kentucky State Reformatory until his release in 1983. Later, he found work as a railroad worker, traveling and working on tracks across the Midwest.

On February 21, 1987, Harry Edward Greenwell attacked 41-year-old Vicki Lucille Heath at the Super 8 Motel in Elizabethtown, Kentucky. After sexually assaulting her, he shot her. The motel lobby showed signs of a struggle, with a telephone ripped from the wall. Her body was later discovered behind a trash bin at the motel.

On March 3, 1989, Greenwell killed two hotel clerks. The first victim was 24-year-old Margaret Mary "Peggy" Gill, who worked the night shift at the Days Inn in Merrillville, Indiana. He sexually assaulted her and shot her twice in the head. Her body was found in a back hallway of the motel. Just four hours later, Greenwell attacked and killed 34-year-old Jeanne Gilbert at the Remington, Indiana Days Inn. He also sexually assaulted her and shot her, with her body being found near the roadway by a passing motorist. Greenwell stole a total of $426 from the two motels.

On January 2, 1990, Greenwell attacked a 21-year-old hotel clerk at the Days Inn in Columbus, Indiana. The clerk survived the assault, which involved a sexual attack, stabbing, and robbery. She was able to provide a description of her attacker, which led to a composite drawing. DNA evidence later connected this attack to the murders in 1989.

In 1991, Greenwell assaulted and stabbed another woman in Rochester, Minnesota. This victim also survived and gave a description of the assailant, which matched the earlier descriptions.

The murders and assaults went unsolved for many years. In 2008, DNA evidence linked the cases. By 2010, law enforcement identified them as connected to one serial killer. In 2022, a DNA match confirmed that Greenwell was the killer. He had been dead since 2013, and investigators were considering the possibility that he might have committed other violent crimes in the Midwest.