Alexander Wayne Watson Jr. was born on September 24, 1969, in Anne Arundel County, Maryland.

On October 8, 1986, Alexander Wayne Watson Jr. committed his first murder. He killed 34-year-old Boontem Anderson in her home in Gambrills. Her body was found by her fiancé's son in the bathtub. Boontem had been sexually assaulted, stabbed, and strangled. At the time, Watson was a minor and lived nearby. He knew the family through their son, who worked at the same fast-food restaurant as him.

On May 23, 1988, Watson murdered again. He targeted 37-year-old Mary Elaine Shereika while she was out for her morning jog. She did not arrive at work, which led her fiancé to report her missing. Later that day, her body was discovered in a farmer's field. Mary was partially clothed and had been raped, stabbed, and strangled. Watson, who lived close to her as well, had seen her jogging that day before he decided to attack her.

The next victim was 14-year-old Lisa Kathleen Haenel. She disappeared on January 15, 1993, while walking to school. Her body was found in a ravine behind Old Mill High School the next day. Lisa was almost completely nude except for a sock and showed signs of having been stabbed and strangled. Unlike the previous victims, she had not been sexually assaulted, but DNA evidence was collected from an unsmoked cigarette found near her body.

Watson's last murder occurred on June 13, 1994, when he killed 37-year-old Debra Cobb during a robbery at her workplace in Forestville. He worked in the same office plaza and was arrested shortly after. He pleaded guilty to first-degree murder, citing his addiction to crack cocaine as a factor in his actions.

After being sentenced to life in December 1994, Watson was sent to Jessup Correctional Institution. It was not until years later that DNA technology linked him to the earlier murders. In 2004, he was charged with the three additional killings. At his trial in 2007, he pleaded guilty to avoid the death penalty and received four more life sentences to serve concurrently with his previous sentence. He was then moved to North Branch Correctional Institution, where he remains.