AUGUSTA, Maine — An Ellsworth woman who has been imprisoned 11 years for killing her father after he subjected her to years of reported emotional, physical and sexual abuse is expected to see her sentence reduced by 18 months.

Gov. John Baldacci’s office announced late Monday that he plans to commute the sentence of Carol E. Graves, now 48, for the May 1996 slaying of her father, 71-year-old Douglas Graves.

It’s the first commutation by Baldacci as governor.

“Twelve years ago, Ms. Graves was involved in a violent act that ended in the death of her father. But the violence did not begin or end on that day in May,” the governor said in a statement. “For more than 30 years, Ms. Graves had been severely abused. That’s not an excuse, but it does help to explain what happened that day.”

Baldacci was traveling Monday and could not be reached for further comment, but communications director David Farmer confirmed that Carol Graves has been notified of the decision. Attempts to reach Graves at the Maine Correctional Center in Windham on Monday evening were unsuccessful.

The Ellsworth woman, nicknamed Sunshine, was charged with shooting and killing her father on May 14, 1996, inside his mobile home off Route 1. According to a history of the case released by the governor’s office, Graves suffered decades of horrific abuse at the hands of her father.

She reportedly was suicidal on the morning of the shooting and had a gun with her when she went to her father’s house to give him his medication and breakfast. From there, she intended to take her own life, the case history stated. Instead, Douglas Graves did what he often did with his daughter: that is, he verbally and physically abused her.

Patrick Larson, who represented Graves during her court proceedings, said the encounter that morning represented the breaking point for his client.

“As I understood it, she was always the one responsible for taking care of him and he responded by abusing her,” said Larson, now a prosecutor with the Maine Attorney General’s office.

Instead of committing suicide, Graves shot her father once in the head and two more times with a .22-caliber handgun. She learned in prison that she suffered from battered women’s syndrome and post-traumatic stress disorder at the time of the killing, according to information from Baldacci’s office. However, she never pursued that defense because she didn’t want people to know that her father abused her.

Graves pleaded guilty to a manslaughter charge and was sentenced in June 1997 to serve 17 years in prison.

“But the [Attorney General’s Office] was firm in proceeding with murder charges,” Larson said. “At the time, a manslaughter plea was the best deal she could have made.”

The former defense attorney remembered Graves as a nice person who committed an act that was totally out of character.

Farmer stressed that when the governor officially signs Graves’ commutation, which could come as early as this week, she will not be released immediately.

“She still has three years left on her original sentence so this would cut that in half,” he said. “She’s not walking out tomorrow.”

With good time earned, Graves was scheduled to be released in September 2011, but with the commutation, her new release date would be March 2010, the governor’s office indicated.

Commutations in Maine are rare. David Loughran, spokesman for the state Attorney General’s Office, said Monday that he couldn’t find documentation of the last case.

Farmer pointed out that there is an important distinction between commutations, which lessen existing sentences, and pardons, which are granted after sentences have been served. He agreed that commutations are much more rare.

Graves’ initial request was filed in June 2005 to the governor’s board on executive clemency. That committee made a unanimous recommendation to Baldacci, who considered her case very carefully before agreeing to the commutation, according to Farmer. One of the things Baldacci noted was Graves’ involvement in educational programs while at the Maine Correctional Center, particularly her support for domestic violence victims, Farmer said.

The Attorney General’s Office will draft a warrant of the commutation and send it to the governor’s office for Baldacci’s signature.

“Ms. Graves has served a long sentence,” the governor’s statement read, “And she has earned an opportunity to show she has turned her life around.”