Sarasota County detectives built a DNA-based family tree with more than 800 branches from volunteer samples and a genealogical database that linked a former Sarasota man to the brutal murder of Deborah Dalzell — a Sarasota attorney and accountant who was strangled in her home in 1999.

Sarasota County Sheriff Tom Knight and Captain John Walsh announced at a press conference Wednesday that Luke Edward Fleming, of St. Petersburg, now 39, was arrested Sunday in Manatee County and charged with murder and sexual battery in the 19-year-old homicide case.

"On March 29, 1999, this evil person turned her paradise into a nightmare," said Peggy Thistle, Dalzell’s sister, who spoke Wednesday on behalf of the family. "As a family, we have dreamed of the day that we would get the news that they caught their killer. We now have a face and name for this monster."

Friday is Dalzell’s birthday, she said, adding "Happy Birthday, Deborah."

The break in the case came in the form of DNA samples obtained from semen collected during Dalzell’s autopsy and entered into a law enforcement database called the Combined DNA Index System, (CODIS). In 2016, Parabon NanoLabs used the database to create a genetic profile that predicted the suspect had fair skin, brown to hazel eyes, and black or brown hair.

The advanced forensic tools that were unthinkable almost 20 years ago were used to build a composite image of Fleming, which investigators compared with past suspects to develop new leads and interview other persons of interest.

Sheriff Knight called it a "good day" for his agency, the community, and the Dalzell family, who have dreamed of a resolution.

"What led to his arrest was unlike anything you have heard in the State of Florida," Knight said, while standing next to the composite image and Flemings’ recent mug shot. "The man you see here today is charged with sexual battery and murder of Deborah Dalzell. His arrest didn’t happen overnight, and it wasn’t easy tracking him down."

Parabon re-analyzed the suspect’s DNA in September using new technology to obtain a genealogical report that identified relatives of the suspect. After weeks of work and hundreds of people identified, a chart revealed a man known as Joseph Fleming who was connected to Sarasota. He had two sons, Jesse and Luke, who lived at 5185 Magnolia Pond Drive — seven-tenths of a mile from Dalzell’s home in 1999.

Jesse Fleming is a convicted felon and is in the CODIS database, which eliminated him as a suspect, leaving Luke as the only "viable, living relative," Walsh said.

Detectives said a DNA sample obtained through "investigative means" was analyzed and confirmed that Fleming left DNA on the body of Dalzell. He was arrested by the Manatee County Sheriff’s Office on Sunday and transferred to the Sarasota County jail on $1.2 million bail.

Fleming, who moved from Brooklyn to Sarasota in 1991, had been working as a cook for the past year at a seafood restaurant. He attended public school in Sarasota and graduated from Riverview High School in 1997.

The murder took place when Fleming was 20 years old.

Walsh said Fleming was charged with domestic battery in 2002 and had recently lived alone in Pinellas County. The detective said the Sheriff’s Office needs help to answer questions they still have, but did not elaborate on those questions.

Thistle thanked Sheriff’s investigators for their "endless hours of work" and "incredible passion and loyalty shown to Deborah in never giving up." She delivered a message from her elderly mother.

"For 20 years, he has been able to see the sun, breathe the air, and see the flowers. May today be the last day," Thistle said. She also had advice for the families of other crime victims who may be waiting for answers. "My message would be to persevere. Don’t lose hope; keep going."

Deborah Dalzell case

Dalzell was killed sometime during the night of March 28, 1999. She was found the next day by deputies, who were sent to her home after her coworkers became concerned when she failed to show up for work.

Dalzell declined a dinner invitation from her sister the night she was murdered.

She said she was weary from putting in extra hours, as she often did as office manager at KMC Telecom, and from going over her sister’s income tax return. She decided to spend a quiet evening at her newly built home in the 5300 block of Colony Meadows Lane.

At about 10:30 p.m., Dalzell spoke on the phone to her sister about the income tax forms. It would be the last known conversation for Dalzell.

Dalzell’s home was in a mostly incomplete subdivision. She had not yet bought window coverings for her bedroom, where she sometimes fell asleep while watching television.

Because the landscaping behind her home had yet to grow, passersby on Honore Avenue, just west of Colony Meadows Lane, had an unobstructed view into her bedroom.

Sometime between that 10:30 p.m. phone conversation and 6 a.m., someone stood on the pool pump and climbed a six-foot wall at the house, cutting a screen to get inside the pool area, which had no exterior door.

The intruder most likely chose not to enter through the open bedroom window, detectives said.

The suspect found Dalzell in her bedroom and started to beat her. Detectives would not say precisely how Dalzell died, other than that no weapon was used in the killing.

"It was someone’s hands," detectives said at the time.

Her jaw was dislocated. There was terrible bruising, and she was sexually assaulted.

Deputies went in through the window and discovered Dalzell’s body in her bathroom. Burglary was not a motive; relatives later could find nothing of value missing.

Just three homes in the subdivision, which was then mostly vacant lots, were occupied. Those residents claimed to have heard nothing suspicious.

Detectives believed at the time Dalzell was most likely killed by a stranger.