Mark James Asay was born on March 12, 1964, in the United States. Limited public records exist about his early life, but it is known that he lived in Jacksonville, Florida, at the time of his crimes. Prior to the murders, Asay was not widely known to law enforcement for any significant or violent criminal history. He had familial relationships — notably a brother named Robbie — and moved in social circles that were reportedly immersed in nightlife activities such as bar hopping and prostitution.

Accounts from his trial and police investigations describe Asay as having harbored racial prejudices, as evidenced by his language and actions during the crimes. There is no documented history of employment or education that has been widely publicized, and the profile of his life leading up to the murders suggests a pattern of impulsive behavior, alcohol abuse, and poor judgment rather than a calculated or methodical criminal path. His crimes, while severe, were not premeditated over a long period, distinguishing him from typical serial killers. His actions, however, were extreme, lethal, and committed within a short timeframe — earning him the classification of a spree killer.

On July 17, 1987, Mark James Asay, his brother Robbie, and a friend named Bubba went out in Jacksonville, Florida. They visited several bars, where they drank beer and played pool. In the early hours of July 18, they decided to go downtown to look for prostitutes. While there, Robbie started to talk to a 34-year-old man named Robert Lee Booker. Asay became angry and began shouting racial slurs at Booker. The situation escalated into a confrontation, during which Asay pulled a gun from his back pocket and shot Booker in the abdomen. Although Booker tried to run away, he later died from his injuries. His body was discovered later that day.

After this shooting, Asay and Bubba continued to seek out prostitutes. They encountered a person named "Renee," who they thought was a woman willing to engage in sexual acts. Unknown to Asay and Bubba, Renee was actually Robert McDowell, a 26-year-old mixed-race man who dressed as a woman. After some discussion, they agreed to a deal. Bubba drove Asay and McDowell to an alley, with McDowell following them. Once in the alley, Asay stepped out of the truck and then returned, grabbing McDowell and pulling him from the vehicle. Asay shot McDowell six times as he tried to escape. Asay then drove away. McDowell's body was found shortly after the shooting.

Asay later spoke to two people about the killings. He claimed he shot McDowell because he thought he had been cheated out of ten dollars in a drug deal. These individuals told police about Asay, leading to his arrest. He was charged with two counts of first-degree murder. During his trial, Asay was found guilty and sentenced to death for both murders.

Asay faced multiple appeals of his sentence, but they were denied. After several years, he was issued an execution warrant, and on August 24, 2017, he was executed by lethal injection at Florida State Prison. The method of execution involved a new drug combination that had not been used in Florida before. Asay was pronounced dead at 6:22 p.m. and made no final statement. His last meal included fried pork chops, fried ham, French fries, vanilla swirl ice cream, and a Coke. His execution was significant as he became the first white person executed in Florida for killing a black person.