Nearly 37-years after 29-year old Teresa Lee Scalf was brutally murdered in her Lakeland home, the Polk County Sheriff’s Office investigation can finally be closed following the analysis of DNA which confirmed the identity of her killer.
With assistance from Othram, Inc., a private lab specializing in forensic genetic genealogy in cold case investigations, PCSO Homicide detectives were able to determine that Donald Douglas was responsible for the death of Ms. Scalf. Donald Douglas died of natural causes in 2008 at the age of 54. He was 33-years old at the time of Ms. Scalf’s murder.
Making the connection was made more difficult since Douglas had no criminal history and his body was cremated after he died, therefore his DNA was never able to be obtained by law enforcement and put into a database for comparison.
The attack and murder of Teresa Scalf occurred in the afternoon of Monday, October 27, 1986.
PCSO detectives determined that the attack was sexually motivated. Ms. Scalf’s neck had been severely cut, and she had significant defensive wounds on her hands.
There were no obvious suspects at the time.
Among the evidence that was collected at the scene was some blood that didn’t come from the victim. It was submitted and entered into the Combined DNA Index System (CODIS), a consortium of local, state, and national databases of DNA profiles from convicted offenders, unsolved crime scene evidence, and missing persons.
For more than three decades, the sample remained unmatched to any known individuals.
Then, in 2022, the PCSO partnered with Othram, Inc. on the case. Othram, Inc. analyzed the suspect’s blood and they were able to narrow the scope to distant relatives of the still unknown suspect. Interviews were conducted with those relatives, and eventually detectives narrowed their search down to close relatives of Donald Douglas who lived directly behind Ms. Scalf at the time of her murder. Douglas had been interviewed by detectives in 1986 during a routine canvass, but at that time, there was no evidence to link him to the murder.
The direct connection to the identity of the murderer came about after detectives obtained a sample of DNA from a son of Donald Douglas. The results of a genetic analysis of the DNA confirmed that the blood found at the murder scene did indeed belong to Donald Douglas, because the DNA profile indicated a 100% confidence of a parent/child biological relationship compared to Douglas’ son’s DNA profile.
“We are extremely grateful for the assistance from Othram, Inc., who provided us with multiple investigative leads and ultimately the missing genetic evidence needed to bring this investigation to a successful conclusion. With their help, our detectives were able to negotiate through a family tree that led to the identity of Teresa Scalf’s killer. I want to thank Mr. Douglas’ son, who was cooperative and willing to assist our detectives. Thanks to Othram, Inc., our detectives hard work, and Mr. Douglas’ cooperation, we were able to help bring long-awaited closure to Theresa Scalf’s devastated family.”
– Grady Judd, Sheriff
The State Attorney Office 10th Judicial Circuit determined the case should be cleared as solved with the offender deceased.
PCSO Homicide Detectives informed Ms. Scalf’s family of the results of the investigation.