DALLAS, Texas (AP) -- Near the end of her short life, Shayla Stewart, a diagnosed manic-depressive and schizophrenic, assaulted police officers and was arrested for attacking a fellow customer at a Denton Wal-Mart where she had a prescription for anti-psychotic medication.

Given all those signs, her parents say, another Wal-Mart just seven miles away should have never sold her the shotgun she used to kill herself at age 24 in 2003.

Her mother, Lavern Bracy, is suing the world's biggest store chain for $25 million, saying clerks should have known about her daughter's illness or done more to find out.

The case, filed earlier this month, has reignited a debate over the confidentiality of mental health records and the effectiveness of background checks on would-be buyers of guns.

"We know that if they had so much as said, `Why do you want this?' we would not be having this conversation because Shayla would have had a meltdown," said her stepfather, Garrett Bracy.

The Bracys said Wal-Mart's gun department could have checked Wal-Mart's own security files or the pharmacy department's prescription records before selling her the weapon.

Wal-Mart spokeswoman Christi Gallagher declined to comment on the lawsuit.

But pharmacy prescription records are confidential under a 1996 federal law, so stores cannot use them when deciding whether to sell a gun.

Also, Wal-Mart did a background check on Stewart, as required under federal law, but through no fault of its own, her name did not show up in the FBI database. The reason: The database contains no mental health records from Texas and 37 other states.

Texas does not submit mental health records because state law deems them confidential, said Paul Mascot, an attorney with the Texas Department of State Health Services. Other states have not computerized their record-keeping systems or do not store them in a central location for use by the FBI.

Federal law prohibits stores from selling guns to people who, like Stewart, have a history of serious mental illness.

Would-be buyers must fill out a form that asks about mental health. Stewart, who had been involuntarily committed to an institution and declared dangerously mentally ill by a judge, lied on that form, according to her mother's attorney's office. Wal-Mart ran a background check anyway, as required by federal law.

Michael Faenza, president and chief executive of the National Mental Health Association, applauds Texas' refusal to share information with the FBI database. He said it would not be fair to violate patients' privacy when there is no data to support claims that mentally ill people are more violent than others.

"The tragedies that families face when people are killed is terrible. And frankly I wish handguns were not so available in this country," he said. "But it's not right, in our minds, to make social policy based on just a few cases."

Garrett Bracy couldn't disagree more.

He and his wife watched his stepdaughter's six-year decline from straight-A high school student to violent and unpredictable stranger. She was hospitalized five times, twice under court orders. Her longest hospitalization, lasting a month, came in 2002 after she refused to leave her room or take her medication.

The suggestion that Wal-Mart should have checked prescription records infuriates Erich Pratt, a spokesman for the Virginia-based group Gun Owners of America.

"Does that mean mental illness prevents everyone on Prozac from owning a gun? Or women with PMS?" he said.

Rep. Carolyn McCarthy, D-New York, who ran for Congress after her husband was killed and son wounded in 1993 by a gunman on a Long Island Rail Road train, wants to strengthen the federal background check system by encouraging states to share mental health records. She has introduced legislation that would give states grants to automate and turn over the information.

She drafted the bill after a priest and a parishioner were shot to death by a schizophrenic man in a New York church in 2002. He, too, should not have been allowed to buy a gun.

"When you see these deaths that could have been prevented it's a shame," McCarthy said.

As the Bracys prepare for another Christmas without their daughter, they are urging lawmakers to support McCarthy's bill and dealers to conduct their own background checks.

"Lavern went to the store the other day to buy over-the-counter headache sinus medication and they limited the amount of sinus medication she could buy at one time," her husband said, his voice trembling with emotion. "But Shayla can walk into a store and buy a gun and they could care less. That's got to change."