LAFAYETTE — An appeals court has tossed out the murder conviction and life sentence of a woman accused of shooting her boyfriend in 2009, ruling that prosecutors failed to offer enough evidence to prove that she intended to kill the man.

Mary Henderson Trahan, 48, argued at trial that her boyfriend, George Barbu, had been waving a pistol around during an argument and that she had persuaded him to give her the gun, which accidentally fired when she slipped and fell.

Prosecutors argued the woman meant to shoot Barbu, and a jury in 2010 convicted Trahan of second-degree murder after a one-day trial.

The state 3rd Circuit Court of Appeal, in an opinion released Wednesday, reversed that conviction. The judges ruled prosecutor Daniel Landry failed to present enough evidence supporting the murder charge or even lesser charges of manslaughter and negligent homicide.

Landry said he will ask the state Supreme Court to review the decision. The question of whether the evidence was strong enough “was a question of fact for the jury to find.”

The reversal shows jurors sometimes assume guilt without careful consideration of evidence, said Crowley attorney John Clay Lejeune, who argued the appeal but did not represent Trahan at trial.

“I think that the burden of proof and the concept of reasonable doubt have been damaged,” Lejeune said. “People assume guilt and then forget about the burden.”

There was no dispute at trial that Trahan shot her boyfriend at close range.

At issue in the appeals decision was whether the prosecutor provided enough evidence to prove the shooting was intentional rather than accidental.

Landry had told jurors in opening and closing arguments that Trahan and Barbu had been fighting and that Trahan shot her boyfriend in anger. But the three-judge appeals panel wrote that there was no actual evidence presented at the trial to support Landry’s statements.

“The prosecutor’s statements to the jury were merely words,” the judges wrote. “Not one piece of evidence was introduced to prove an argument or that the defendant was angry at the victim.”

In addressing whether Trahan could face the lesser charge of negligent homicide, the appeals judges wrote that the prosecution offered no evidence of how the shooting occurred and that “its own witnesses could not rule out the possibility that the shooting was accidental.”

The decision by the three-judge appeals panel was 2-1, with Judges Ulysses Gene Thibodeaux and Jimmie C. Peters voting for reversal, and Judge Shannon J. Gremillion dissenting.

Gremillion agreed with the other two judges that the evidence was insufficient to prove murder but wrote in a dissenting opinion that the evidence could have supported the negligent homicide.

“Pointing a loaded gun at the victim — even if the gun was accidentally discharged — exhibits a gross deviation below the standard of care expected from a reasonable careful person,” Gremillion wrote.