Half-brothers who four years ago came within 16 hours of execution for a woman's murder in Florida were set free yesterday after pleading guilty to second-degree murder, according to their defense attorneys.

The men -- William Riley Jent and Earnest Lee Miller -- made their pleas in a brief appearance in a Florida courtroom as part of an agreement worked out between their lawyers and the state attorney's office. In accepting their pleas, Pasco County Circuit Court Judge Maynard Swanson Jr. sentenced them to 12 years, but immediately released them because of the time they had already served and time off for good behavior.

Jent, 36, and Miller, 31, had spent more than eight years on Florida's death row for a murder that they claimed they never committed. Last November, a federal judge ordered a new trial for them after defense attorneys argued that the men were wrongly convicted by a jury that was not presented crucial evidence.

Despite yesterday's pleas, Jent and Miller maintained their innocence outside of the courtroom.

Miller told the Associated Press that they accepted the plea agreement because "we were up against the same system as last time . . . . It was tearing our family apart."

"They framed us once," Jent told Associated Press. "What was to stop them from doing it again? If they want us to say we committed perjury, let them prove we were innocent of murder. I'll take the perjury charge."

Lawyers for the defendants said the plea agreement was bittersweet. "I'm happy for Bill and Ernie today because they are alive . . . but the taste is bitter because the price was a lie," Eleanor Jackson Piel, a lawyer for Jent, said last night.

"Anytime that anybody can walk out of death row is virtually a miracle," said Howardene Garrett, a defense lawyer who has been involved in the case since 1983.

However, Doug Crowe of the Pasco County state attorney's office told the Associated Press, "The issue of guilt is resolved. We were satisfied they committed the murder before plea negotiations began. In this case, I'm certain innocent people were not induced to plead guilty."

From the beginning, the case was controversial. The murder victim was never fully identified. Key witnesses changed their stories. Some claimed they were pressured to recant. Law enforcement officials failed to pursue several leads.

The murder victim was finally identified in 1985 after a Washington Post reporter, who was investigating the conviction of Jent and Miller, linked a set of fingerprints in Tennessee of a missing woman, Linda Gale Bradshaw, to prints taken from the partially burned body of the murder victim. They matched. The Florida Department of Law Enforcement then conducted its own investigation and concluded that the victim was Bradshaw.

That was a relief to Bradshaw family members, who had maintained since 1979 that the badly burned corpse was that of Linda Gail Bradshaw. The body, buried in a pauper's grave, was finally turned over to the family in August 1986.

Defense lawyers claim that the identity of the murder victim is important to the case because there is a witness who says he saw Bradshaw killed by her boyfriend, Charles Robert (Bobby) Dodd Jr. Bradshaw family members also believe Gail Bradshaw was killed by Dodd, who is currently in a Georgia jail on unrelated charges.

Last night, Bradshaw's sister, Ruby Vaughn, said, "I'm glad that the boys are free, but now that they have admitted guilt, that means they {law enforcement officials} will never do anything to Bobby Dodd."

Vaughn said she understood why the men took the plea agreement. "I don't blame the boys because they have lost eight years of their lives," she said. " . . . There is no guarantee that they would get out alive."

After yesterday's hearing, Piel said Miller and Jent, appearing at a news conference, asked Bradshaw's family to pardon them.

Last November, when U.S. District Court Judge George Carr in Tampa ordered a new trial for the two men, Carr said the prosecutors had withheld "favorable evidence" from defense lawyers, evidence that came to light after two Florida newspapers successfully argued before an appeals court that the sheriff's reports on the murder should be released. Prosecutors, who had earlier persuaded a lower court to deny access to the records, made the reports public in 1986.