A Douglas County teenager accused of stabbing his great-grandmother to death with a sword will get another mental evaluation to determine whether he is competent to stand trial.

Channel 2 Action News reported a judge on Wednesday granted a defense request for a new evaluation, even though an earlier evaluation determined Gevin Prince was competent to face trial in the Aug. 15 death of Mary Joan Gibbs, 77.

Prince, 15, waved to family members as he walked into court and responded with short, polite answers to confirm his not-guilty plea, according to Channel 2.

District Attorney David McDade said he was impressed with the teenager’s demeanor.

“He appears to understand,” McDade said Wednesday. “His lawyer advised the court he understands. The doctors evaluating him say he's capable of understanding.”

Prince’s defense attorney, Travis Glahn, however, said that while his client may appear to understand, Prince cannot grasp the seriousness of the charges because he suffers from Asperger's syndrome, which is similar to autism.

“For a 15 –year-old kid that's basically living in an adult jail, I think he's holding up pretty well,” Glahn said. “Obviously, I think, every day's a challenge with him.”

Prince faces malice murder and aggravated assault charges in the incident last summer that left Gibbs dead and seriously injured Laura Prince, Gevin Prince's grandmother.

Gevin Prince was taken into custody after about a 10-minute standoff with law enforcement officers. He is also accused of chasing two teenagers off with a sword as they tried to help Gibbs just before she died.

Laura Prince told the AJC that the older her grandson got, the more he “acted out” physically, eventually prompting 911 calls to county authorities. She said the August incident began as a disagreement over the youth’s use of a home computer.

The teen's family members on Wednesday repeated an earlier position that prison isn’t the best place for the teen despite the seriousness of the crime.

“I don't think he’ll make it,” Gibbs’ son, David Cook, told Channel 2. “I think they'll kill him in prison, but we have to try him, hopefully try him and get him in a place he needs to be.”