DENVER (AP) — Jurors found a Colorado woman guilty of murder in the death of her 11-year-old stepson on Monday, rejecting her claim that she was insane when she attacked him.

Letecia Stauch was convicted of all charges she faced in Gannon Stauch’s killing over three years after prosecutors said she stabbed Gannon 18 times before hitting him in the head and then shooting him once. Prosecutors claimed Stauch killed the boy in January 2020 because she hated him and wanted to hurt his father, Al Stauch, whom she planned to leave and who was away on a National Guard deployment at the time.

Stauch did not deny killing Gannon and taking his body across the country in a suitcase in the back of a rented van. But she pleaded not guilty by reason of insanity. The defense argued that she killed Gannon during a “psychotic break” caused by trauma from being physically, emotionally and sexually abused during her childhood.

Experts at the state mental hospital concluded that Stauch had a personality disorder with borderline and narcissistic features but was sane at the time Gannon was killed. Under Colorado law, that means understanding the difference between right and wrong and being able to form the intent to commit a crime.

The main defense witness, Dr. Dorothy Lewis, author of the book “Crazy, Not Insane” and featured in an HBO documentary with the same title, concluded Stauch suffered from dissociative identity disorder — when someone has two or more personalities as the result of trauma — and was not sane at the time Gannon was killed.

Prosecutors, however, pointed out that Lewis did not know how sanity is defined under Colorado law.

In the weeks leading up to Gannon’s killing, Stauch was diagnosed with generalized anxiety disorder after she was referred to a psychologist while being treated military health clinic. Therapist Ronda Niederhauser testified that Stauch did not show any signs of being a threat to herself or others and was aware of her surroundings.

Authorities believe Stauch killed Gannon in his bedroom a few hours before reporting him missing on Jan. 27, 2020, saying he had not come home from playing with friends. Dozens of volunteers helped search for the boy in the area around where the family lived near Colorado Springs. However, investigators later revealed that Stauch concocted a variety of stories to mislead them, including that a man she hired to repair a carpet raped her and then abducted Gannon.

After Al Stauch became suspicious of his wife, he allowed the FBI to listen in on his phone calls with Stauch, trying to draw out more information from her about where Gannon was. Hours of audio from those calls along with video recordings of interviews with Stauch about her mental health were a prominent part of the evidence offered during the five-week trial.

Gannon’s remains were found by bridge inspectors in March 2020, in a suitcase under a bridge on the Florida Panhandle. Prosecutors suggested that Stauch snuck out from a hotel room where she was staying with her daughter in Pensacola to dispose of his body in the middle of the night, hoping it would be swept into the Gulf of Mexico.

Stauch was convicted of first-degree murder after deliberation, first-degree murder of a child by a person in a position of trust, tampering with a deceased human body and tampering with physical evidence.

She did not appear to show any reaction to the verdict as it was read, sitting at the defense table between her two lawyers. Later, as everyone milled around court talking, she sat there alone, taking sips of water.