LAKELAND, Fla. — Polk County Sheriff Grady Judd said a violent, decades-old murder was solved by a cold case detective tracing genealogy DNA back to an affair by a suspect's distant family member in 1949.
Theresa Scalf was a 29-year-old nurse at Lakeland Regional when she was found dead on October 27, 1986. Judd said she was found by her mother after she didn't show up for work.
Judd said Scalf was aggressively stabbed, and her head was almost cut off.
Now, nearly 40 years later, Judd said cold case detectives determined that the person responsible was Donald Douglas, a man who was 33 at the time and who lived behind Scalf.
“He showed up at her house with what looked like he yanked a flower out of the ground and slapped it into a pot. He was sort of stalker-ish. She told us about him but she never described him," said Lynn Scalf, Scalf's sister.
Judd said detectives believe Douglas murdered Scalf after some type of rejection. Judd said detectives at the time of the murder talked to Douglas during canvasses of the neighborhood but said Douglas was "never ever" on the radar.
How a distant family member's affair led to the suspect
Judd said the original detectives on the case preserved unknown blood found at the scene. They ran it in the 2000s when CODIS, or the Combined DNA Index System, came along, but they never got any matches.
In 2015, cold case detective Matthew Newbold took on the case.
"He kept her picture on his wall, and he told me — he told me — I will not retire until I solve this case, and he did," Pam Shade, Scalf's sister, said of Newbold.
In 2022, Newbold partnered with Othram Inc. to start the painstaking process of tracing the unknown DNA. Judd said Newbold traced the DNA back to a third cousin in 1949 who had an affair with a neighbor and then had a subsequent child.
Detectives then used those findings to locate Douglas' son, who provided a DNA sample. Judd said the son was certain his dad wasn't involved and was cooperative. He was "in horrible shock" when it matched, the sheriff said.
Judd said Douglas, who died of natural causes at age 54, was never arrested for anything.
"The most loving person"
"Theresa was a wonderful person, the most loving person. She didn't deserve this. Our family didn't deserve this," Shade said.
Scalf lived alone in her apartment with her 8-year-old son, who wasn't home at the time she was killed.
Family members said her mom, Betty, used a credit card to break into Scalf's apartment when the hospital called and said she didn't show up for work.
"I'm 84 years old, I lived to see this done. I think that's why I lived so long," Betty said during Monday's press conference.
Shade credited Scalf with leading almost their entire family to work in healthcare. Shade herself became a nurse after she said her sister encouraged her to. She said she's worked as a nurse for 38 years.
"My family and I are moving forward in an attempt to just get past this," Shade said. "We would just like to thank everybody."
She encouraged others in similar situations to never give up.
For his part in solving the murder after nearly 40 years, Det. Newbold said: "I just feel good for the family."
