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DALLAS (CBSDFW.COM/AP) – A state judge has ruled a man mentally competent to be executed Dec. 7 for fatally shooting his two young daughters more than 15 years ago in Dallas while their mother, his ex-wife, listened helplessly over the phone.

State District Judge Robert Burns ruled Friday after a two-day hearing earlier this week for 61-year-old John David Battaglia.

The U.S. Supreme Court has declared that a prisoner can be executed if he or she is aware the death penalty is set to be carried out and has a rational understanding of why.

Three psychologists testified the former accountant doesn’t understand why he’s scheduled to die. A fourth said Battaglia is faking his delusions.

A federal appeals court stopped Battaglia’s scheduled lethal injection March 30 so the competency questions could be reviewed.

Three psychologists testified that Battaglia is delusional and should not be executed. But another told the judge Battaglia is putting on an act and had been fully cooperative when he needed to be.

As far as the information presented to the court, former Dallas County prosecutor Toby Shook said earlier in the week he thought the state may have the inside edge.

“One expert gave testimony that he believes he’s malingering, that he’s faking mental illness. Also, the state produced evidence that the defendant had looked up how to become incompetent.”

It was 2001 when Battaglia shot and killed Faith and Liberty, his 9- and 6-year-old daughters, in his Deep Ellum apartment.

He had picked up the children from his ex-wife in the parking lot of a shopping center for a court-ordered and scheduled visit. Battaglia was under a court order to stay away from his ex-wife’s Highland Park home.

Not long after the girls were given to Battaglia, he got his former wife, Mary Jean Pearle, on the phone. “Why do you want daddy to go to jail,” one of the girls reportedly said to Pearle over the phone. Seconds later, Pearle heard one of the children say “No, no, daddy,” then gunshots.

(©2016 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)