Lois Ann Goodman's lawyers told The Associated Press that she passed a privately administered polygraph examination, testing as truthful when she denied any role in her husband's death.
Lawyers for the 70-year-old Goodman said they suggested the district attorney reevaluate the case based on the results and consider dismissing the charge.
District attorney's spokeswoman Sandi Gibbons said prosecutors will not comment until the material is brought up in court.
Goodman's attorney Robert Sheahen said polygraph technology has become an accepted form of investigating cases in recent years and sometimes leads authorities to either file charges or drop them.
"This is a technique used by many major law enforcement agencies in the country," Sheahen said. "Some cases rise and fall on the polygraph."
The FBI trains polygraphers, and Jack Trimarco, the expert who administered Goodman's test, was FBI trained and has done testing in a number of high-profile cases.
Although polygraphs are used by the government and in private industry, the one place they are generally not used is in criminal courts where most states ban them from jury trials.
"The sole reason the courts don't use them is they say the jurors are the lie detectors in a trial," said Sheahan. "They feel the polygraph usurps the province of the jury."
A few states allow polygraph evidence if both sides in a trial stipulate to it.
Goodman's attorneys said they have emailed the results of her test to the district attorney's office.
The lead detective on the case, David Petique, had asked Goodman to take a polygraph test to clear herself when she was first under investigation in the month after her husband's death, attorneys Alison Triessl and Robert Sheahen said. But she refused that request on May 3, they said, on advice of her former counsel.
Sometimes attorneys oppose such requests because it can be seen as a waiver of Fifth Amendment protection against self-incrimination.
Goodman's attorneys said she has now fulfilled the request and passed.
"I'm hopeful that they are going to reassess their case," Triessl said in a phone interview. "The facts just don't support that there was a murder. The results of the polygraph prove Lois Goodman did not kill her husband. He died in a freak accident."
Goodman, who has refereed matches between some of tennis's greatest players, has pleaded not guilty to killing her 80-year-old husband by beating him with a coffee cup and using its broken handle to stab him. She has suggested Alan Goodman fell down the steps while holding a coffee cup, causing his fatal injuries.
Alan Goodman died in April. Authorities initially believed he fell down stairs at home while his wife was away but later decided it was homicide after a mortuary reported suspicious injuries on Alan Goodman's head.