US  | 

Florida Executes Man Who Killed Wife's Sister, Parents

David Pittman's execution was state's record 12th of the year, with 2 more scheduled
By Newser Editors and Wire Services
Posted Sep 17, 2025 5:44 PM CDT
Florida Carries Out Record 12th Execution of the Year
Clouds hover over the entrance of the Florida State Prison in Starke, Florida.   (AP Photo/Curt Anderson, file)

A Florida man convicted of killing his estranged wife's sister and parents and setting their house on fire was put to death Wednesday in what was a record 12th execution in the state this year. David Pittman, 63, was pronounced dead at 6:12pm ET following an injection at Florida State Prison near Starke under a death warrant signed by Gov. Ron DeSantis, the AP reports. Florida's Republican governor has signed more death warrants this year than any of his predecessors.

  • DeSantis spokesperson Alex Lanfranconi said the execution was carried out without complications. Pittman's last words were, "I know you all came to watch an innocent man be murdered by the state of Florida. I am innocent. I didn't kill anybody. That's it," according to Lanfranconi. Pittman's final appeal was rejected on Tuesday by the US Supreme Court.

  • Pittman was convicted and sentenced to death in 1991 on three counts of first-degree murder, according to court records. Jurors also found him guilty of arson and grand theft. Pittman and his wife, Marie, were going through a contentious divorce in May 1990, when the killings occurred, and investigators say he had threatened to harm her family several times.
  • Trial testimony showed Pittman cut a phone line at the Mulberry, Florida, home of his wife's parents, Clarence Knowles, 60, and his wife, 50-year-old Barbara Knowles. Pittman stabbed the couple to death as well as their other daughter, 21-year-old Bonnie Knowles. Pittman then set their house on fire and stole Bonnie Knowles' car, which he also set ablaze. The family was found dead on May 15 of that year.
  • A witness during his 1991 trial identified Pittman as the person seen running away from the burning car. A jailhouse informant testified that Pittman had admitted to the killings. Jurors recommended the death penalty on a 9-3 vote.

  • Pittman's most recent appeals focused on recent evidence indicating he suffers from intellectual disabilities, including an IQ in the low 70s, that was apparent at the time of the killings. His lawyers had argued that his execution would violate the Constitution's protection against putting a person with severe mental problems to death.
  • Lawyers for the state disagreed, contending it came too late for Pittman to claim mental impairment from years earlier. The Florida Supreme Court, reversing a previous decision, had ruled in 2020 that such claims could not be applied retroactively.
  • So far, two more Florida executions are scheduled for this fall. Victor Tony Jones is set to die on Sept. 30 for the 1990 killings of two people during a robbery and Samuel Lee Smithers is scheduled to be executed on Oct. 14 for the murders of two women in 1996.

Read These Next
Get the news faster.
Tap to install our app.
X
Install the Newser News app
in two easy steps:
1. Tap in your navigation bar.
2. Tap to Add to Home Screen.

X