Luke Fleming was arrested Sunday night for the 1999 rape and murder of Deborah Dalzell. Authorities say a genealogical DNA search led investigators to Fleming, nearly 20 years after the murder. (Image: Courtesy of the Sarasota County Sheriff's Office)

The semen left behind at the scene of a brutal rape and murder resulted in a genealogical search that captured the killer, authorities announced.

The slaying of Deborah Dalzell on March 29, 1999 went unsolved for nearly 20 years, until the weeks-long searches of family trees pinpointed a man who lived within a mile of her home, the crime scene.

The arrest of 39-year-old Luke Fleming on Sunday night marks the 11th arrest involving lead provided by the Parabon NanoLabs genetic genealogy program.

“We now have a face and name for this monster,” said Peggy Dalzell Thistle, the victim’s sister, at a press conference this morning.

Deborah Dalzell was murdered on March 29, 1999. On Sunday, Luke Fleming was arrested in her murder case, following a genealogical DNA search using genetic material found at the crime scene. (Photo: Courtesy of the Sarasota County Sheriff's Office)

The Dalzell cold case was revisited in 2012. A contract with Parabon was struck in 2016 to conduct phenotyping services to predict the killer’s likely appearance in 2016, which developed some leads, according to Capt. John Walsh.

The DNA from the scene never hit in any databases, according to authorities. And the case still had no suspects.

This summer, the autosomal DNA from the sperm cells was used by Parabon to provide lead. Those leads allowed local drectives to produce a genealogical chart homing in on a man named Joseph Fleming, a Florida resident. But Joseph Fleming died in 2001, Walsh said.

A further DNA genealogy search resulted in the identification of Joseph Fleming’s two sons: Jesse and Luke, both of whom lived about seven-tenths of a mile from Dalzell’s home.

Jesse Fleming has a criminal history that had resulted in his DNA already being in CODIS.

But despite a minor criminal history including domestic batter, Luke Fleming’s DNA was never sampled for any of the major databases, according to Walsh.

Luke Fleming was 20 at the time of the Dalzell murder, having graduated form a local high school two years earlier.

Further investigation included collecting a surreptitious sample of DNA from Luke Fleming, and other contextual evidence. The arrest warrant was granted Sunday, and he was cuffed the same day.

Police take a DNA cheek swab from Luke Fleming, who was arrested for the murder of Deborah Thistle this weekend. (Photo: Courtesy of the Sarasota County Sheriff's Office)

Parabon announced its DNA genealogy initiative in the wake of the highly-publicized arrest of the alleged Golden State Killer, Joseph James DeAngelo, in April (Parabon was not involved in the DeAngelo investigation). The other 10 arrests involving Parabon were high-profile murder and serial rape cases across the country. They include:

  • The arrest of Gary C. Hartman in the 1986 murder of Michella Welch in Tacoma, Wash.
  • The capture of Raymond “DJ Freez” Rowe, in the 1992 killing of Christy Mirack, a young schoolteacher, in Lancaster, Pa.
  • Murder and related charges against James Otto Earhart in the murder of real estate agent Virginia Freeman, in Brazos County, Tex., in 1981.
  • The arrest of William Earl Talbott on charges related to the brutal slayings of Jay Cook and Tany Van Cuylenborg, a young couple from British Columbia, in Everett, Wash., in 1987.
  • The capture of John D. Miller, in the rape and murder of 8-year-old April Tinsley in Indiana in 1988.
  • Murder charges against Matthew Norman Dusseault, 21, in the March 2016 murder of 81-year-old Constance Gauthier in Woonsocket, R.I.
  • Rape charges against Spencer Glen Monnett, 31, for an April home-invasion rape of an elderly woman in Utah.
  • The capture of the alleged Ramsey Street Rapist, Darold Wayne Bowden, in connection with six rapes in Fayetteville, N.C., between 2006 and 2008.
  • Last month, the announcement of murder charges against Michael F.A. Henslick in connection with the 2009 home invasion, rape and murder of Holly Cassano in Illinois.
  • Last week, the arrest of Marlon Michael Alexander, now 39, in Maryland for a series of rapes over the course of a decade. 
  • And this arrest of Fleming for the 1999 Dalzell murder.

Parabon is not the only group plying forensic genealogy to crack cold cases.

For instance, the Golden State Killer breakthrough was made by genealogist Barbara Rae-Venter, whose use of forensic genealogy in identifying the “Chameleon Killer,” Terry Peder Rasmussen, one of the first high-profile uses of the technique. Rae-Venter has also been the breakthrough in some other recent cases, in which genealogy was not mentioned by authorities.

The DNA Doe Project, helmed by Colleen Fitzpatrick and Margaret Press, has instead focused on unidentified the deceased and the pioneering use of degraded DNA—such as the case of Joseph Newton Chandler III, an old man who committed suicide in 2002 while living under the assumed name of an 8-year-old boy who died in a car crash in Texas in 1945.

All three groups share one commonality: the use of public genealogical databases, particularly GEDmatch.