A Stanislaus County Superior Court judge ruled a Denair woman was legally insane when she stabbed her father to death and attacked her mother on Mother’s Day 2011.

Shanna Wills, 20, entered a guilty plea Thursday in court to second-degree murder and assault with a deadly weapon causing great bodily injury.

Upon entering the plea, Judge John Freeland ruled Wills was not guilty by reason of insanity, said Stanislaus County Assistant District Attorney Carol Shipley. The attempted murder charge against Wills was dropped as part of the plea deal.

At the age of 17, Wills attacked her father, Kenneth Wills, 62, and her mother Susan Wills at the family home on Salluce Drive in Denair on May 8, 2011.

During a preliminary hearing, the court heard testimony about how Wills’ mental health had been deteriorating in the weeks and months leading up to the attack. Three days prior to the attack, Wills was found wandering outside a rural Denair home and the homeowner said she seemed confused as to how she got there and very frightened.

On that Mother’s Day, Wills had planned an elaborate celebration for her mother that included filling every vase, jar, cup and anything else that held water with flowers cut from the yard. She also cooked multiple food dishes that were piled up in the kitchen, according to one witness. The witness said that when Kenneth Wills saw the scene in his house he got angry with Wills and the two started arguing.

Susan Wills testified at the preliminary hearing that she arrived home around 6:30 p.m. and found her husband and daughter engaged in a verbal onslaught with one another. Susan Wills testified that the dispute turned physical when Wills used a shard from a broken horse statue to slice her father’s forehead. Kenneth Wills went into the kitchen, at which point Wills allegedly hit him with a vacuum and a stand-up electric fan.

According to the prosecution, Susan Wills and her husband were forced into their bedroom by Wills. Susan Wills recalled Wills ordering them to beg for forgiveness and telling them that they wouldn’t be hurt because she had made them angels.

Susan Wills said she was stabbed in the back by her daughter with a decorative knife Wills had picked up during the altercation. The wound punctured Susan Wills’ lung.

The fight between Kenneth Wills and Wills continued until he lay motionless in the hallway. Forensic pathologist Sung-Ook Baik testified that Kenneth Wills sustained six stab wounds and numerous bruises from blunt force traumas. Baik said all the stab wounds but one were superficial. The one fatal wound pierced Kenneth Wills’ intestine. Baik said Kenneth Wills died from blood loss that occurred over 20 to 30 minutes.

The first Stanislaus County Sheriff’s deputies to arrive at the home found Wills in a semi-stupor sitting nude in an overflowing tub.

Sheriff’s Detective Frank Soria interviewed Wills for about three hours and during that time she continually referred to herself as God, the female Jesus, and that she had been sent to rid her parents of their sins.

Two court appointed psychiatrists and a third one contracted by the district attorney’s office, examined Wills over the time she was in custody. All three came to the same conclusion that Wills was incapable of determining if her actions were morally or legally correct at the time of the attack, Shipley said.

“We wanted our own expert to examine her and when he reached the same conclusion it was irrefutable that she was legally insane at the time. We are satisfied with the outcome,” Shipley said.

The case will be referred to the California Department of State Hospitals, which will determine if Wills will be treated at an inpatient facility or as an outpatient.

If she is ordered to an inpatient facility, Wills would be transferred to a state hospital, where she would receive treatment until a time when her doctors and the court determine that she no longer poses a threat to herself or society. That time could be as little as six months or it could be for the rest of her life.

After hospitalization, or as an outpatient, Wills would likely be subject to a conditional release. This means she would have to follow a court ordered treatment plan at a minimum security facility, like a halfway house.

The report determining Wills treatment plan is due to the court by Feb. 10.