New Mexico's top court examines 'warrior-gene' defense

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SANTA FE, N.M. (AP) — The New Mexico Supreme Court debated Monday whether a murder defendant should have been allowed to introduce evidence that he has a genetic predisposition to violence.

At issue is whether a district court acted properly in excluding evidence of a so-called warrior gene variant linked to a predisposition toward aggressive and violent behavior as it weighed murder charges against Anthony Blas Yepez. The Supreme Court listened to oral arguments from opposing attorneys without yet issuing a decision.

Yepez was convicted in the killing of his girlfriend's 75-year-old step-grandfather during a domestic dispute in 2012. He is serving a 22-year sentence for second-degree murder with additional time for auto theft and tampering with evidence.

An appeals court ruled that the lower court abused its discretion in excluding the scientific testimony, but that no harm was done because Yepez was acquitted of first-degree murder charges that require the state prove premeditation.

Seeking a potential retrial, defense attorney Helen Bennett said testimony on Yepez and a possible genetic predisposition to violence still deserved consideration in relation to second-degree murder charges, which don't involve premeditation, and whether Yepez truly had an intent to kill.

"This is a due process issue. The defendant was foreclosed from his right to present his theory," Bennett said. "It's offered to show that he was incapable of forming the kind of intent that is necessary to find him guilty of this."

State prosecutors fear will the appellate court decision will open the door to broader consideration of a "novel and unsubstantiated theory."

"This theory has been around for some time. No appellate court has accepted it." said Maris Veidemanis, an assistant attorney general. "And now we have this opinion. ... You have this finding of an abuse of discretion, and that to me is risky."

Justice David Thomson questioned whether that was enough to warrant intervention by the Supreme Court, considering that the appeals court did not endorse the allegedly risky genetic theory.

"Where is the tempest?" he said. "I really want to know."

Bennett confronted pointed questions about why attorneys for Yepez did not attempt at trial to revive testimony about genetic predisposition when it came to second-degree murder charges and issues of general intent.

"There is not even a suggestion in the record for the district court that the defense counsel even whispered about general intent," Justice C. Shannon Bacon said.

It was unclear how soon the Supreme Court might act on the case.

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