A Fairfax County judge appointed experts Thursday to evaluate whether the man accused in the high-profile killing of Muslim teen Nabra Hassanen is intellectually disabled and therefore barred from facing the death penalty.

Defense attorneys sought the appointment of a neuropsychologist and neurotoxicologist in the capital murder case because they believe Darwin Martinez Torres, 23, of Sterling may have been exposed to neurotoxins while growing up near a major gold mine in El Salvador.

“We hope to present evidence as to why this defendant’s brain functions differently,” attorney Joseph T. Flood told the judge. “If someone has a tainted brain that has been exposed to neurotoxic chemicals, are they less culpable than someone else?”

Flood did not identify the mine but told a judge it had released arsenic and mercury into the groundwater and soil surrounding it. Flood said investigations had uncovered evidence that Torres had possibly been exposed to toxins by drinking polluted water and eating food grown in chemical-laced soil.

Flood said the neuropsychologist appointed by the judge had examined Torres and found he suffered from impairments consistent with exposure to neurotoxins. The issues include cognitive limitations, poor memory and impaired judgment.

He hoped the neurotoxicologist could establish a cause-and-effect link between the gold mine’s chemicals and Torres’s impairment. The Supreme Court has ruled that it is unconstitutional to execute people with significant mental deficits.

Casey Lingan, Fairfax County chief deputy commonwealth’s attorney, objected to the appointment of the neurotoxicologist, saying it would be impossible to know whether Torres had consumed tainted food and water 20-plus years ago. He called the move “neuro witchcraft.”

“There is no scientific link that can be established at this point. . . . It’s all speculative,” Lingan told the judge.

Circuit Court Judge Randy I. Bellows warned Flood that the defense would have to establish evidence that Torres had been exposed to the neurotoxins before he would allow the neurotoxicologist to testify during a January trial.

Torres is facing counts including capital murder and rape in the abduction of Hassanen, 17, as she and a group of teens walked back to their Sterling mosque in June following a predawn meal, a common ritual to mark the holy month of Ramadan.

Police said Torres got into an argument with one of the teens before chasing them in his car and then running after them with a baseball bat. He is alleged to have caught up to Hassanen and hit her on the back of the head.

Police said he then took Hassanen to a location near his apartment complex. Prosecutors said Thursday that Hassanen was raped and killed in an area of vegetation adjacent to a pond, where they said Torres dumped her body.

Hassanen’s killing stirred outrage and fears that she was targeted because of her faith. Vigils were held in cities around the country; police said they have turned up no evidence that she was killed because she was Muslim.

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