A trial for a Warren County teen accused of murder was delayed Monday so she can undergo further mental evaluation.

Circuit Judge Isadore Patrick ordered Tyla Vega, 15, 100 Jones Road, to be committed to the state mental hospital for evaluation following 90 minutes of inconclusive testimony from an expert witness.

“I don’t have the confidence to proceed as is,” Patrick said.

Patrick set a Sept. 4 trial date for Vega, who is accused of shooting her 32-year-old stepmother on May 10, 2011.

Dr. Billy Fox of Clinton testified Monday that he examined Vega four times in March and May but was unable to make a conclusion if Vega was competent to assist in her own defense.

“She didn’t seem to be as concerned about the gravity of her situation as I thought she should be,” Fox said.

Based on the examinations, Fox said, he could not determine how well Vega could participate in her own defense.

Getting Vega to talk about her defense has been difficult, said attorney Marshal Sanders.

“In my mind and in my experience, there is a serious problem trying to communicate with Miss Vega,” Sanders said.

District Attorney Ricky Smith argued that the burden of incompetency lies on the defense and that Fox’s testimony failed to prove Vega was incompetent.

“After an hour and a half, I still have no clue what the opinion of Dr. Fox is,” Smith said.

Tyla Vega is accused of shooting Michelle Vega in the face at their home. Tyla Vega, then 14, was seen driving away from the family’s home minutes before Michelle Vega’s body was found. She was arrested in Greenville after a six-day, multicounty search.

If convicted, Tyla Vega will be granted an automatic appeal because of a U.S. Supreme Court ruling this summer. In a 5-4 ruling June 25, the court struck down laws in Mississippi and 28 other states that impose mandatory life-without-parole sentences on convicted juvenile murder defendants.