According to The Orange County Register, the three-judge panel for the 9th U.S. Circuit Court of Appeals reversed 75-year-old Marvin Vernis Smith's 2007 murder conviction, ruling that Smith didn't receive a fair trial.
Minnie Smith, 66, was found dead in the couple's home. Authorities said she had been beat to death with a metal fireplace log roller on Dec. 15, 2005.
The court ruled that a jury instruction violated Smith's right to receive proper notice of charges against him and prepare a defense.
The District Attorney's Office will request that the State Attorney General ask the U.S. Supreme Court to review the decision.
The Associated Press contributed to this report.