An FBI scientific expert whose disputed hair identification helped send Mascotte police officer James Aren Duckett to Florida's Death Row in 1988 for the on-duty murder of an 11-year-old schoolgirl gave inaccurate testimony and withheld evidence, resulting in the reversal of a Washington, D.C., sexual assault conviction.

The inmate convicted in the Washington case served 10 years and was already on parole when the case collapsed, The Associated Press reported this week.

It is the first reversal arising from an investigation of the FBI crime lab and, more specifically, the work of FBI agent Michael P. Malone.

Duckett, convicted of murder and rape in Lake County, has already spent 15 years on Death Row.

''Every conviction that has been based strongly on the testimony of Michael Malone should undergo intensive review by the courts, especially the case of Jim Duckett,'' said former Miami-Dade Homicide Capt. Marshall Frank. His own investigation convinced him that Duckett is innocent of the murder of Teresa McAbee.

Duckett, now 45, is on ''borrowed time,'' said Frank. The average stay on Death Row before execution is 11.5 years, based on figures between 1977 and 2003.

The little girl's body was found in Knight Lake about half a mile from where she was last seen at a Circle K convenience store near her home the night of May 11, 1987. A hair found in the little girl's panties was first examined by Deborah Steger Lightfoot, a 28-year veteran of the Florida Department of Law Enforcement crime lab.

HAIRS EXAMINED

Now supervisor of the FDLE's Daytona Beach satellite lab, Lightfoot told Frank on Friday that she examined nine or 10 head hairs and fragments of hairs found on the dead child and the pubic hair found in the panties.

Five belonged to the victim, Frank said, two were unidentifiable and three were unidentified. She compared the pubic hair to those from Duckett and Antonio Morales, a boyfriend of the child's mother, Dorothy McAbee, Neither was a match.

''Then the Lake County investigators found Mike Malone,'' says Frank, who points out that a number of other men both lived at and frequently visited the McAbee home. The hair was then sent to Lifecodes, a New York laboratory, to try for a DNA match. None was possible because the hair had no root.

MISSING EVIDENCE

Some of the standard hairs taken from Duckett were missing when the evidence was returned from the lab, according to Beth Wells, Duckett's appellate attorney. New standards were taken from Duckett, and Malone agreed to examine them. ''My professional experience was that if a piece of evidence had already been examined by a certified laboratory analyst, the FBI lab would not accept the evidence,'' said Frank. He supervised 3,000 murder investigations during his 30-year career in Miami-Dade County.

``A certified laboratory was trusted. If our crime lab made a call on a piece of evidence, you never went shopping for another analyst, another agency.''

The government disclosed to defense lawyers in 2001 that Malone had engaged in misconduct in the Washington case. Yet the recent brief filed by the Florida Attorney General's office in response to Duckett's pending appeal to the Florida Supreme Court identifies Malone as ''currently a special agent of the FBI assigned to the Richmond, Virginia office, qualified as an expert in hairs and fibers in 42 states'' and adds that courts ``have never refused to recognize him as an expert.''

There have been questions and allegations about Malone's work and testimony for some time. Florida prosecutors ignored a 1998 book, Tainting Evidence: Inside the Scandals at the FBI Lab, by John F. Kelly and Philippp K. Wearne. Duckett's case is among those cited in the book, with Malone's conclusions refuted by Peter DeForest, professor of criminalistics at John Jay College. Declared DeForest: ``There was no match with the original samples taken from Duckett. However, Malone made a match with a sample they had taken six months later. It suggested to me that somebody had switched something. Certainly something did not smell right.''

Frank said that if DeForest was correct, someone must have discarded the evidence hair in the victim's panties, replacing it with Duckett's. The Associated Press reported in March that an FBI review had identified about 3,000 cases that could have affected by shoddy work, but only 150 defendants had been notified of problems.

OUT OF LAB

Malone was transferred from the lab after the scandal became public but continued to work for the bureau until his retirement, with honors, in December 1999. ''Nobody's convinced anybody in a black robe that I've done anything wrong,'' Malone told Sydney P. Freedberg, a St. Petersburg Times reporter, in 2001. ''I did the best I could,'' he said. ``Crime labs aren't perfect. People aren't perfect.''

But now, in Washington, somebody in a black robe has been convinced.

''Malone is one more nail coming out of [Duckett's] coffin,'' Frank said Friday.

Frank is not the only disturbed investigator. Ron Hill, now 67, a one-time professional wrestling champion known as The Golden Gladiator, is a private detective who has worked on the case pro bono for 15 years. ''Never took a dime,'' he says. ``Not even gas money.''

His conclusion: ``I don't think he is innocent. I know he is innocent.''

Both he and Frank believe the little girl probably was killed in her own home -- never examined by crime-scene technicians -- because the clothing she had on when she was found dead on the muddy bank of the lake was different from what she had on when Duckett questioned her at the Circle K the night before.

WALKED TO STORE

She had walked about 400 feet to the convenience store to buy a pencil after 10 p.m. that night. James Duckett, a rookie cop, spotted her behind the Circle K dumpster with Salvador Calisto, 16. He warned them about a 10:30 p.m. local curfew, and told the girl to go home. At midnight, her mother reported the girl missing.

At the trial, damning video-taped testimony came from Gwen Gurley. Gurley was 16, nine months pregnant, and in jail. She testified she saw Duckett drive away with Teresa in his patrol car.

Ron Hill tracked down Gurley later. She lied, she told him, for special treatment from the police. 'She admitted point-blank how nice she'd had it at the jail. She could come and go as she pleased. They'd take her anywhere she wanted to go. I asked if she felt guilty. She said Duckett `was a nice guy, but I needed to get out of jail.' ''

Gurley recanted her original testimony at least four times, but refused to do so during a 1997 evidentiary hearing because she was threatened with prison for perjury. She took the Fifth Amendment.

At the time, Lake County police said that Gurley's friend, Vickie Davis, 15, had corroborated her story.

Davis, now 30, is an inmate at Lowell Correctional Institution, serving a five-year prison sentence for aggravated battery with a deadly weapon.

''I am incarcerated as well, but I'm guilty of my crime,'' she wrote to Frank. ``Gwen Gurley got me involved.

`I WAS SCARED'

``I'm not even sure I was with Gwen that night . . . Gwen showed up at my house . . . with the police and two detectives asking me to come with them to the station . . . I was scared so they said I wasn't in any trouble to just come and talk. I didn't know anything about the Duckett case until that day, or Gwen's story. The detectives put me and Gwen in a room so we could talk among ourselfs [sic], and that's when Gwen . . . told me to agree to what she said to help her get out of trouble. We discussed it for a while, then brought out to join the detectives with a tape recorder. Gwen and detectives discussed the times and sighting and I just agreed.

``The police . . . kept shutting off the tape recorder to get our story straight and sorted bout, then turned back on when we all came to an agreement.

``I've never been to court or spoken to any prosecutor on this case . . . I do know me and Gwen's story was not true and my conscience lives in guilt over what I've done . . . .''