DNA match leads to South Florida police closing a 38-year-old cold case murder

South Florida police have closed a 38-year-old cold case murder after finally identifying the suspect with DNA evidence.

The Davie Police Department said it has charged Donald Lawless, who is now dead, in the case of the 1987 murder of Marilyn Decker.

The crime happened on Oct. 22, 1987 in Davie. Decker, who was then age 28, was found floating in a canal in the 3000 block of Flamingo Road with multiple stab wounds. Her cause of death was determined to be homicide by asphyxiation, also known as suffocation. 

Davie police said that in the 1980s, multiple suspects were identified but as evidence was collected and processed, there were negative results and the case remained unsolved. 

The investigation continued in 1995 with interviews and more scene items being processed. There were no active leads and there were more negative results, leaving the case cold. 

In 2021, the case was reopened by the Davie PD Cold Case Unit. Possible suspects were interviewed and family members spoke with detectives who had worked on the case previously. Police even featured the case on a Broward Crime Stoppers billboard. 

Davie police then took the case to DNA experts in California. Multiple hairs found in Decker’s shirt were processed, revealing that it had a male’s DNA. The DNA was taken to a chief genealogist who, after months, presented Davie PD with a possible suspect. 

The suspect was identified as Lawless, who would now be 100 years old. 

According to Davie police, Lawless lived in Florida from the early 1980s through 1993. He had an extensive criminal past dating back to the 1940s and lived in Davie. 

Lawless died in Ohio in 1995 and was cremated, but Davie police said officers were able to obtain DNA from a close relative of Lawless to compare to the DNA found on Decker’s shirt. 

Police had success and were able to match it to Lawless. 

Davie police then turned the case over to the Broward County State Attorney’s Office, which determined there was enough evidence to charge Lawless with the murder of Decker.