Death warrant is signed in 1990 Polk murders
By News Service of Florida
August 16, 2025 at 9:02 AM EDT
David Pittman was convicted in the May 1990 murders of his wife’s parents in Mulberry.
In what could be the 12th execution this year in Florida, Gov. Ron DeSantis on Friday signed a death warrant for a man convicted of killing three members of his estranged wife’s family in 1990 in Polk County.
David Pittman, 63, is scheduled to be executed Sept. 17 at Florida State Prison, according to documents posted on the Florida Supreme Court website. Florida has already set a modern-era record this year with nine executions, and two more men are scheduled to be put to death by lethal injection this month.
Pittman was convicted in the May 1990 murders of his wife’s parents, Clarence and Barbara Knowles, and their 20-year-old daughter, Bonnie. At the time of the murders, another daughter, Marie, was seeking to divorce Pittman, who was opposed to the divorce, according to court documents.
The Knowles’ home in Mulberry also was set on fire.
“Although all of the bodies were burned in the fire, a medical examiner determined that the cause of death in each instance was massive bleeding from multiple stab wounds,” a 1994 Florida Supreme Court opinion rejecting an appeal said. “In addition, the medical examiner testified that Bonnie Knowles' throat had been cut.”
Pittman was convicted in 1991 on murder, arson and grand-theft charges.
The Pittman death warrant came as Florida prepares to execute Kayle Bates, 67, on Tuesday in the 1982 murder of a woman abducted from a Bay County insurance office where she worked. Also, Curtis Windom, 59, is scheduled to be executed Aug. 28 in the 1992 murders of three people in Orange County.
Bates’ attorneys Thursday appealed to the U.S. Supreme Court to try to halt his execution, while Windom’s attorneys have an appeal pending at the Florida Supreme Court. The 11th U.S. Circuit Court of Appeals on Friday rejected a separate attempt to halt Bates’ execution.
At the Atlanta-based appeals court, Bates’ attorneys had alleged racial disparity in how Florida selects inmates to be executed. Bates is Black. But a three-judge panel of the appeals court turned down the argument.
“Bates has not alleged that the decisionmakers in his particular case acted with discriminatory purpose,” said Friday’s seven-page decision shared by Chief Judge William Pryor and Judges Kevin Newsom and Britt Grant. “Instead, he relies solely on statistical evidence that the governor implemented his warrant-selection process in a racially discriminatory fashion.”
The previous modern-era record for executions in a year in Florida was eight in 1984 and 2014. That era represents the time after the death penalty was reinstated in 1976, following a U.S. Supreme Court ruling that halted it in 1972.
In a filing Thursday at the U.S. Supreme Court, Bates’ attorneys pointed to short amounts of time to try to fight the death warrants in court.
“Something is wrong in Florida,” Bates’ attorneys wrote. “Governor DeSantis is signing death warrants at an unprecedented pace … with no sign of slowing down. In each warrant, he designates a week in which the Florida Department of Corrections will execute an inmate. With minor variations, this weeklong window begins 30 days after the warrant is signed. Florida State Prison’s warden has invariably scheduled executions on the first possible day, allowing the briefest period in which to litigate constitutional issues and save the condemned man’s life.”
David Pittman, 63, is scheduled to be executed Sept. 17 at Florida State Prison, according to documents posted on the Florida Supreme Court website. Florida has already set a modern-era record this year with nine executions, and two more men are scheduled to be put to death by lethal injection this month.
Pittman was convicted in the May 1990 murders of his wife’s parents, Clarence and Barbara Knowles, and their 20-year-old daughter, Bonnie. At the time of the murders, another daughter, Marie, was seeking to divorce Pittman, who was opposed to the divorce, according to court documents.
The Knowles’ home in Mulberry also was set on fire.
“Although all of the bodies were burned in the fire, a medical examiner determined that the cause of death in each instance was massive bleeding from multiple stab wounds,” a 1994 Florida Supreme Court opinion rejecting an appeal said. “In addition, the medical examiner testified that Bonnie Knowles' throat had been cut.”
Pittman was convicted in 1991 on murder, arson and grand-theft charges.
The Pittman death warrant came as Florida prepares to execute Kayle Bates, 67, on Tuesday in the 1982 murder of a woman abducted from a Bay County insurance office where she worked. Also, Curtis Windom, 59, is scheduled to be executed Aug. 28 in the 1992 murders of three people in Orange County.
Bates’ attorneys Thursday appealed to the U.S. Supreme Court to try to halt his execution, while Windom’s attorneys have an appeal pending at the Florida Supreme Court. The 11th U.S. Circuit Court of Appeals on Friday rejected a separate attempt to halt Bates’ execution.
At the Atlanta-based appeals court, Bates’ attorneys had alleged racial disparity in how Florida selects inmates to be executed. Bates is Black. But a three-judge panel of the appeals court turned down the argument.
“Bates has not alleged that the decisionmakers in his particular case acted with discriminatory purpose,” said Friday’s seven-page decision shared by Chief Judge William Pryor and Judges Kevin Newsom and Britt Grant. “Instead, he relies solely on statistical evidence that the governor implemented his warrant-selection process in a racially discriminatory fashion.”
The previous modern-era record for executions in a year in Florida was eight in 1984 and 2014. That era represents the time after the death penalty was reinstated in 1976, following a U.S. Supreme Court ruling that halted it in 1972.
In a filing Thursday at the U.S. Supreme Court, Bates’ attorneys pointed to short amounts of time to try to fight the death warrants in court.
“Something is wrong in Florida,” Bates’ attorneys wrote. “Governor DeSantis is signing death warrants at an unprecedented pace … with no sign of slowing down. In each warrant, he designates a week in which the Florida Department of Corrections will execute an inmate. With minor variations, this weeklong window begins 30 days after the warrant is signed. Florida State Prison’s warden has invariably scheduled executions on the first possible day, allowing the briefest period in which to litigate constitutional issues and save the condemned man’s life.”