A man convicted of raping and killing a college student yelled "murderers!" three times as he was put to death by lethal injection.
Eric Scott Branch thrashed about on his stretcher and shouted and screamed before he fell silent.
He was pronounced dead at 7.05pm on Thursday at Florida State Prison.
The 47-year-old was executed for the 1993 rape and fatal beating of University of West Florida student Susan Morris.
The 21-year-old's naked body was found buried in a shallow grave near a nature trail.
"She had been beaten, stomped, sexually assaulted and strangled. She bore numerous bruises and lacerations, both eyes were swollen shut," judges who rejected one of Branch's previous appeals at the Florida Supreme Court had noted.
Court records also showed he was convicted of sexually assaulting a 14-year-old girl in Indiana and of another sexual assault in the Florida Panhandle that took place just 10 days before the college student was brutally killed for her car.
His murder trial jury recommended the death penalty by a 10-2 vote under Florida's old capital punishment system, which was ruled unconstitutional by the US Supreme Court years later because jurors had failed to reach a unanimous decision.
Florida legislators subsequently changed the system to comply.
Asked later whether Branch's outburst could have been caused by the execution drugs, Department of Corrections spokeswoman Michelle Glady said "there was no indication" that the inmate's last actions were a result of the injection procedure.
This was confirmed by the Florida Department of Law Enforcement, she added.
The college student's family said afterwards in a statement: "Twenty-five years ago, Susan's life was suddenly and brutally extinguished.
"We have grieved for her longer that she was with us. Yet because of who she was … she will never be forgotten by those who love her."
Meanwhile, 38-year-old Thomas "Bart" Whitaker, who hired a gunman to kill his mother and brother at their Houston home had his death sentence commuted, less than an hour before he was set to be executed.
The last-minute reprieve – from Texas governor Greg Abbott, a Republican – came after the death row inmate's father who survived the 2003 attack pleaded with the state to grant clemency.
The execution of Doyle Lee Hamm for the 1987 death of a motel clerk during a robbery was postponed in Alabama after the inmate argued there was a risk of a botched execution because of damage to his veins from lymphoma and other illnesses.
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The US Supreme Court delayed the execution to consider Hamm's appeal, later giving it the go-ahead. However, it left officials with little time to prepare him for the execution and his death warrant expired at midnight.