When a death warrant was signed last summer for Roberto Arguelles, questions were raised about the state of the convicted killer's mental health.

In court hearings, Arguelles, 41, would spit and shout obscenities, rambling in long incoherent sentences. In his cell at the Utah State Prison, he ate his own feces, court documents and plastics.

The Department of Corrections asked the court for a competency evaluation to ensure the inmate understood the ramifications of the death warrant. But Arguelles, who raped and murdered four women, died of natural causes last fall before that evaluation was complete.

His case raised questions for state attorneys, who found that mental illness was not defined in Utah law. The standard for determining one's competency was unclear. The question of what should occur when a condemned person is found incompetent also was not addressed.

Legislators are now being asked to clarify those issues in SB49, sponsored by Sen. David Gladwell, North Ogden. Last year, Gladwell carried the bill that made it illegal for Utah to execute those found to be mentally retarded.

Incompetency related to mental illness could include dementia from Alzheimer's, brain injuries, severe mental illnesses such as schizophrenia or other diseases.

The U.S. Supreme Court decided in 1986 that the clinically "insane" could not be executed.

Utah law already includes competency standards for those facing trials, which includes the ability to participate in one's defense, said C.C. Horton, an assistant attorney general who drafted SB49. But the standard for competency for execution was "left open" and those being executed need to understand the reason for the proceedings, he said.

"It can't be that they think they are being executed because they looked funny at a guard," said Horton. "We are talking about people who, because of a mental defect, don't understand why they are about to die."

The Senate Judiciary and Law Enforcement Committee passed the bill 5-0.

Before the vote, Fraser Nelson of the Disability Law Center asked lawmakers to delay the bill for study during the year ahead. She expressed concerns that under the bill a mentally ill person could be rendered competent through medications, after which he or she would be executed by the state. Those concerns are shared by the Utah District Branch of the American Psychiatric Association, she said.

"(Psychiatrists) are willing to provide medical treatment to improve the quality of life of a condemned individual but will not participate in treatment that is solely for the purpose of restoring competency (so they could be) executed," Nelson said, reading from a prepared statement.