Laura Prince stood on the porch of her Douglasville home, her arm still wrapped in a sling, three days after her own grandson, Gevin Prince, attacked her and killed his great-grandmother Mary Joan Gibbs with a samurai sword.

“I will love him unconditionally,” Laura Prince told Channel 2 Action News’ Richard Elliot.

Gevin, 15, is charged as an adult with murder and aggravated assault. Deputies said he stabbed Gibbs to death with a samurai sword and injured Prince’s arm. Police arrested him after a short standoff where, they said, he used a pellet gun to shoot out the windows of a police car. Investigators said this wasn’t the first time they went to Prince’s home because of the teen.

Prince didn’t want to discuss the details of the attack but said her grandson, who lives with her, is autistic and on a great deal of medication. She also believes he is bipolar, although he was never diagnosed.

Even though he wounded her and killed her mother, she still defends him and doesn’t agree with Douglas County District Attorney David McDade’s decision to charge Gevin as an adult. She said she plans to call McDade to discuss the possibility of treating Gevin as minor.

“He’s not emotionally or mentally old enough to stand trial as an adult,” Prince told Elliot. “I know it was an adult crime, but he was not an adult.”

Prince describes her grandson as being more like an 8 or 10-year-old-boy rather than a 15-year old. She said he was a math whiz who could draw architectural designs by hand but could only read and write on a first-grade level.

Prince also said he is gentle and needs treatment in a medical facility, not jail time.

“He was a little kid,” she said. “He wanted to be 15, but he was young for his age.”

Meanwhile, Prince said her mother wanted to be cremated and her ashes spread across Tybee Island near Savannah, a place she loved to visit.

Gevin remains in the Douglas County Jail.