The Dallas County district attorney's office has for the second time dismissed a murder charge against a doctor accused of killing his wife.

Prosecutors determined that evidence in the case could provide three explanations of how Sara Werner might have been fatally shot, one of the prosecutors said Thursday.

The first explanation, the one Farmers Branch police believed when they arrested Timothy Werner, is that he killed his wife. The second is that she was shot during a struggle. The third is that Sara Werner took her own life.

"It was clear to everybody how unclear it was," said prosecutor Josh Healy, who said he and fellow prosecutor Mindy Sauter found the evidence troubling as they prepared for a January trial date. "In good conscience, going forward, now – it wouldn't be right."

Timothy Werner, 57, has always maintained that his wife of 11 months committed suicide on April 19, 2004. Sara Werner was 47 and had struggled with drugs and alcohol.

But her family has said she could not have committed suicide, noting that she was about to enter a rehabilitation program and seemed excited about changing her life.

Timothy Werner's attorney, Reed Prospere, said that the district attorney's office did not tell him why the case was dismissed, and he did not ask. But he said that when Werner was arrested the second time, prosecutors were "under the impression that they had additional blood evidence that was going to be favorable to a crime being committed."

Healy said the new blood spatter evidence, along with previous blood and ballistics evidence, did not provide clear information about how Sara Werner was shot.

Healy said that the few particles of gunshot residue found on one of Timothy Werner's shirts could have been transferred from his wife's body, and not from the gun. Blood also was found in the shower and on the doctor's clothes, but he said there wasn't enough evidence to determine how it got there.

Prospere, who said that Werner passed a polygraph test after his first arrest, called the DA's dismissal of the case "an admirable stance."

Werner could not be reached for comment.

Sara Werner's mother said she is disappointed the case is not going to trial.

"The wound keeps opening up," said Jean Josch, 81, of Marble Falls. "I'm saddened because I was hoping it would go to trial, and we would have some closure. I thought the trial might bring that."

Josch said she didn't think her daughter would kill herself.

"That did cross my mind," she said. "God is the only one who knows that for sure."

Farmers Branch police declined to comment about the case.

Timothy Werner was first arrested in 2005, but the case was dismissed the following year.

In 2007, Farmers Branch police asked the DA's office to re-examine their files. In April 2008, the Dallas County medical examiner's office ruled Sara Werner's death a homicide. It was previously listed as pending. Timothy Werner was arrested again in May 2008, and the charge was dismissed Wednesday.

Healy said the autopsy report still lists Sara Werner's death as a homicide, but said that he had not updated the medical examiner about the case's dismissal.

Timothy Werner's medical license was suspended in December because he did not comply with orders from the Texas Board of Medical Examiners. He had been ordered in April 2008 to participate in a drug screening program, abstain from prohibited substances, receive monthly psychiatric treatment, attend five Alcoholics Anonymous meetings a week and limit his practice to 40 hours a week.

He was previously accused of giving a controlled substance to his wife even though she was known to have a drug problem. The board said he oversaw her detoxification without documenting the treatment and allowed her access to his prescription pad.

Prospere said that Timothy Werner, who he said was severely impaired by a heart attack last year, was taking the steps he needed to resume practicing medicine.

"As much as he was disappointed about being indicted two times, he has the satisfaction of knowing justice was done here," Prospere said.

But Healy said the dismissal doesn't mean the case is over. He said the DA's office would be open to new information that could explain what happened. Another problem with the case, he said, is that one witness is out of the country and another committed suicide.

"It's not done, but let's just say it's not on the front burner," Healy said.

Staff writer Jon Nielsen contributed to this story.