Frank Athen Walls was born on October 12, 1967, in Ocean City, Florida. Very little is known about his early life. He began committing crimes when he was young, including burglaries and peeping on women. He also had a history of animal abuse. Walls worked as a dishwasher at a restaurant called "Quincy's" when he started his crime spree. During this time, he lived with a roommate named Thomas "Animal" Farnham. Farnham later said he was uneasy around Walls because Walls often spoke about dark subjects, such as killing people. Despite his troubling behavior, Walls dated the stepdaughter of Mark Riebe.

Frank Athen Walls committed his first murder on March 26, 1985. He was on Okaloosa Island doing community service when he attacked 19-year-old Tommie Lou Whiddon. He approached her while she was sunbathing and cut her throat with a knife. Afterward, Walls took her car, which was later found abandoned. Whiddon's body was discovered the same evening by someone walking on the beach.

On September 16, 1986, Walls killed his second victim, 24-year-old Cynthia Sue Condra, in Wright. He stabbed her 21 times and left her body on the side of a road.

The following year, on May 20, 1987, Walls broke into a mobile home occupied by 47-year-old Audrey Gygi. It is believed he raped her and then returned to kill her. After confronting Gygi again, he stabbed her to death. Her body was found the next morning after a co-worker reported her missing.

Walls' most infamous crimes occurred on July 22, 1987. He entered a mobile home in Ocean City, where he found 20-year-old Edward K. Alger and his girlfriend, 22-year-old Ann Louise Peterson. He caused a disturbance to wake them up. When they checked on the noise, Walls forced Peterson to tie them up. Alger managed to loosen his bindings and fought back but was ultimately overpowered. Walls cut his throat and shot him three times in the head. He then assaulted Peterson and shot her, killing her as well. After the murders, Walls stole items from the home, including cash and a fan.

Walls was arrested on July 24, 1987, after his roommate alerted the police about his behavior. He faced multiple charges, including two counts of first-degree murder. Evidence linked him to the crime scene, and he later confessed to the murders.

During his time in custody, investigators looked into other unsolved murders, including that of Audrey Gygi, using DNA evidence. They found a fingerprint from Gygi at Walls' trailer. In 1994, Walls admitted to killing Gygi, Whiddon, and Condra, in exchange for not facing prosecution for the latter two.

After his arrest, Walls went through several trials. He was found guilty of the murders of Alger and Peterson and received the death penalty for Peterson's murder. His sentence was confirmed in a second trial in 1992, which found him guilty again.

Over the years, Walls faced several appeals, primarily based on claims of mental incapacity and intellectual disability, all of which were denied. As of March 2025, Walls remains on death row awaiting execution. His crimes have left a lasting impact on the community of Okaloosa County.