Arthur Shawcross was born on June 6, 1945, in Kittery, Maine, but he grew up in Watertown, New York. From a young age, his life was filled with trouble. He claimed he was abused by his family and bullied at school. As he grew older, he struggled with his behavior and had difficulty fitting in. After dropping out of high school, he joined the army and served in Vietnam.

After being discharged from the Army, Arthur Shawcross moved to Clayton, New York, with his wife, Linda. However, Linda soon divorced him, and Shawcross began committing crimes like arson and burglary. These offenses landed him a five-year sentence at Attica Correctional Facility and later Auburn Correctional Facility. After serving 22 months, he was released early for helping rescue a correctional officer during a prison riot. Returning to Watertown, New York, Shawcross found a job with the Watertown Public Works Department and got married for the third time.

On May 7, 1972, Shawcross committed his first known murder. He lured 10-year-old Jack Owen Blake into a wooded area in Watertown, where he raped and killed him. Blake's body wasn't found until September 5, when authorities received a tip. Just days before this discovery, on September 2, Shawcross raped and killed eight-year-old Karen Ann Hill, who was visiting Watertown with her mother for Labor Day. Shawcross was arrested the following day. He was indicted for Hill's murder and, on October 17, 1972, pleaded guilty to a lesser charge of first-degree manslaughter for both deaths, receiving a sentence with a maximum of 25 years at Attica Correctional Facility.

After serving 14 years in prison, Shawcross was released on parole in April 1987, despite warnings from psychiatrists who labeled him a "schizoid psychopath." He struggled to settle down as communities protested his presence, moving from Binghamton to Delhi, then to Fleischmanns, and finally to a transient hotel in Rochester. By October 1987, he found more permanent housing in Rochester. In March 1988, Shawcross began a new killing spree, targeting prostitutes in the Rochester area. Over the next two years, he murdered eleven women, with another death suspected but not officially attributed to him.

On January 5, 1990, Shawcross was arrested after being spotted near where one of his victim's bodies was found. At his trial in November 1990, Shawcross pleaded not guilty by reason of insanity. His defense claimed he had brain damage, multiple personality disorder, and post-traumatic stress disorder. However, the prosecution argued he had antisocial personality disorder. Despite these claims, Shawcross was found guilty of ten murders and sentenced to life in prison without parole. He was incarcerated at the Sullivan Correctional Facility until his death. During his imprisonment, he gave interviews where he bragged about his crimes, including cannibalism, further revealing the depth of his disturbed mind.