Convicted killer Brian Steckel was executed early Friday by lethal injection for a 1994 rape and murder, the governor's office said.
Steckel, 36, was pronounced dead about 12:21 a.m. (0521 GMT), a prison official told protesters outside the prison.
Steckel was sentenced to death in 1997 for the 1994 murder of Sandra Lee Long in her apartment near Wilmington. Long was burned to death in a fire Steckel set after strangling her into unconsciousness and raping and sodomizing her.
The U.S. Supreme Court refused without comment Thursday to block the execution. The court's refusal to grant his appeal came shortly before a brief rally by about 30 death penalty opponents outside the legislative building in Dover.
Despite the small number of protesters, Sandra Dean, an attorney for the state public defenders office, said she believes such rallies have "a slow, persistent effect" that she and others hope will lead to the abolition of capital punishment.
Steckel's last meal was cheese steak, cole slaw and Pepsi, and he spent final hours sleeping, eating reading, writing letters and talking to prison staff, family members and friends and his attorney.
Gov. Ruth Ann Minner issued a statement shortly after the execution was carried out, saying that "I pray that the completion of this sentence, recommended by a jury and imposed by a judge, will bring some amount of closure to Ms. Long's family. May God have mercy on Mr. Steckel."
While awaiting trial in prison, Steckel sent more than 75 taunting and threatening letters to prosecutors, a judge and others involved in the case. In one of seven letters sent to Long's mother, Virginia Thomas, he enclosed a copy of an autopsy report on which he had scribbled, "Happy, happy, joy, joy ... Read it and weep. She is gone forever. Don't cry over burnt flesh."
Defense attorneys argued unsuccessfully in state courts that the jury in Steckel's trial was misled into believing that its decision on whether he was eligible for the death penalty would be only a recommendation to the judge during the penalty phase of the trial, instead of a final , AP reports.