Thomas Otis Knight was born on February 4, 1951, in Fort Pierce, Florida. He was the second oldest in a large family with nine children. Knight's home life was troubled. His father struggled with alcohol addiction and was known to be violent. He often beat his children and once committed a terrible act against Knight's sister while Knight was present.

Knight's early years were marked by trouble with the law. By the time he was nine years old, he had been arrested several times for theft. As a teenager, he continued to get into trouble. At the age of fifteen, he was convicted of burglary and sent to state prison.

When Knight turned nineteen, he was sent to the Northeast Florida State Hospital in Macclenny. There, he was diagnosed with issues related to drug and poison intoxication, as well as a paranoid personality disorder. These early experiences shaped his life and were significant as he grew older.

On July 17, 1974, Thomas Otis Knight kidnapped Sydney and Lillian Gans in Miami. He forced Sydney, his boss, to drive to their home to collect Lillian. Afterward, he demanded they go to a bank to withdraw $50,000. While Sydney went inside the bank to get the money, Lillian was driving Knight around. Sydney informed bank staff about the situation, leading them to call the FBI. When Sydney came back to the car with the cash, police were following them. They lost sight of the vehicle but later found it abandoned in a secluded area. Both Sydney and Lillian were discovered dead nearby, having been shot in the neck.

While awaiting trial for their murders, Knight escaped from Miami-Dade County Jail on September 19, 1974, with ten other inmates. After a few days, most were recaptured, but Knight and two others were still free. During this time, Knight committed a series of armed robberies. On October 21, 1974, he and an accomplice robbed a liquor store in Cordele, Georgia. During this robbery, he fatally shot clerk William Culpepper and injured another clerk, stealing $640.

Knight was placed on the FBI's Ten Most Wanted list on December 12, 1974. He was captured on December 31, 1974, at a rooming house in New Smyrna Beach, Florida. He was armed and had barricaded himself but was taken into custody by an FBI SWAT team. Following his arrest, he was sentenced to death for the murders of the Gans couple on April 21, 1975.

On October 12, 1980, while on death row, Knight killed corrections officer Richard Burke with a sharpened spoon. He was angry because the prison would not allow him to see his mother. After this incident, he received another death sentence for Burke's murder on January 20, 1983.

Knight's execution was delayed multiple times due to various appeals. In 1987, a federal ruling removed his original death sentence for the Gans murders, as he had not been allowed to present certain witnesses during his penalty phase. He spent thirty-nine years on death row. His execution finally took place on January 7, 2014, through lethal injection at Florida State Prison. He had a last meal that included sweet potato pie and ice cream, but he did not make a final statement. During his time on death row, he converted to Islam and changed his name to Askari Abdullah Muhammad.