The attorney for 70-year-old tennis referee Lois Goodman claims there is no DNA evidence on the coffee cup his client allegedly used to bludgeon her elderly husband to death.
Attorneys for Goodman said they hope the DNA evidence, coupled with a lie detector test they say the referee passed, will help exonerate her of murder charges.
Alan Goodman, 80, died in April at his California home. The referee said she found her husband dead in bed. She said she believed he had crawled there to rest after a terrible fall.
Investigators initially believed Alan Goodman had fallen down the stairs, but later classified the death as a homicide after suspicious head injuries were reported.
In August, shortly before she was scheduled to oversee a match at the U.S. Open, Lois Goodman, who was in uniform, was arrested in New York City.
Prosecutors said they believe the 70-year-old left her husband for dead in April, while going off to a tennis match and to get a manicure.
Goodman has maintained her innocence and insisted her husband died after he fell down the stairs and hit his head on a coffee cup.
"My mother would never do something like this ever, not in a million years," said Goodman's daughter, Allison Rogers. "She's completely innocent."
The defense hired a polygraph expert, Jack Trimarco, to administer a lie detector test to Goodman. He concluded the longtime referee is an "innocent woman."
"I asked, did you kill Alan Goodman? And at your residence, did you kill your husband?" he said. "There was no physiological reaction attached to those answers that she gave, which were no."
While the defense hopes the lack of DNA evidence will exonerate Goodman, law enforcement experts aren't so sure.
"It doesn't really matter whether her DNA was found or not," said former FBI agent and ABC News consultant Brad Garrett. "In fact, it's not uncommon for a suspect's DNA to not be a murder weapon, whether it be a gun, a knife [or] in this case, a coffee cup."
ABC News' Mark Greenblatt contributed to this report.