Theresa Beerman walked into a gun store in north Houston about a week before Christmas.

The Woodlands woman wanted to buy a handgun, and she did. She took the offered free training, then climbed into her vehicle, drove around the block and used the gun to kill herself.

Beerman, 26, was one of the tens of thousands of Americans who used a firearm to end their lives in recent years.

It's not how her father wants to remember her. When John Beerman thinks of Theresa, he recalls a smart, vibrant woman who loved the outdoors, loved reading and who dreamed of working as a psychologist.

But he remembers, too, her battle with mental illness, the ups and downs that began when she was 16. There were suicide threats and interventions over the years.

Now, more than a month after his daughter's death, John Beerman is speaking up because he says more needs to be done.

"It's just unthinkable," said Beerman, who lives in Windsor, Co.

More Information If you need help If you or someone you know is struggling with suicidal thoughts, help is available. Call the National Suicide Prevention Hotline at 1-800-273-8255.

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Advocates against gun violence say no measure would necessarily have prevented Theresa's death, though several measures could substantially curb similar incidents.

'Her mind wasn't right'

Theresa Beerman's death - which came amid other high-profile gun deaths in recent months - draws attention to gaps in the gun purchasing and federal background check process, her father said.

"If there could have been some kind of way they could have held her for 48 hours, to do a little more research on her, to find out," he said. "She had a history of mental illness in Montgomery County and Colorado Springs. ... I don't think she knew what she was doing; I think she didn't realize the permanency of her decision. Her mind wasn't right."

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According to information from the Centers for Disease Control and Prevention, more than 40,000 Americans killed themselves in 2013, the most recent year for which data is available. Of that number, more than half were performed with a gun.

Beerman's death is the latest to raise concerns about guns falling into the hands of people who shouldn't have them, with fatal consequences.

After the Sutherland Springs shooting - in which a former U.S. Airman shot up a church, killing 26 - officials with the U.S. Air Force said they had failed to report Devin Patrick Kelley's previous record of domestic violence to a federal database used for background checks.

And earlier this month, after a murder-suicide in Galveston, friends of the shooter, Flor de Maria Pineda Cañas, said she had committed the act after a long and troubling history of mental illness.

At Spring Guns & Ammo, the shop where Beerman bought her gun, a spokesman said the 26-year-old Montgomery County woman had filled out a required federal 4473 form, passed a background check and given no indication she planned to use the gun to end her life.

"We followed every ounce of the law, to the letter," the spokesman said, declining to be identified. "We're really sorry about the whole thing. It's obviously something we never want to happen ever again, but as far as our standpoint, we 120 percent followed the letter of the law."

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The form Beerman filled out has specific parameters detailing when stores licensed to sell firearms must deny the sale to potential customers, said Nicole Strong, special agent and spokeswoman for the Houston field office of the Bureau of Alcohol, Tobacco, Firearms and Explosives.

For a potential customer to be barred from buying a gun because of past problems with mental illness, that person would have had to have been labelled "mentally defective" by a judge, she said. An involuntary mental health commitment or other past encounters with law enforcement would not necessarily bar that person from purchasing a gun.

The names are then run through the National Instant Criminal Background Check System, or NICS, database.

"If she filled out a 4473 and they did a background check and she passed, she gets to leave with a gun," Strong said. "That's how the system works ... The only fix would be for Congress to change the law. As it stands now, she was not in violation. She was allowed to legally buy and possess a gun."

More checks needed

To curb gun suicides, mental health advocates say the federal background check system should be expanded to include broader prohibitions against those with mental illness. State and federal laws should also be expanded, they say, so that family members of those seeking to purchase firearms can weigh in if they are concerned their loved ones may harm themselves.

"Guns are very easy to use and very highly lethal," said Liza Gold, clinical professor of psychiatry at the Georgetown University School of Medicine and editor and contributing writer of the book, "Gun Violence and Mental Illness."

"Any step you take that delays or postpones or restricts someone's access to guns creates an opportunity for someone else and intervene to prevent a suicide," Gold said.

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Current law prohibits only the most severely mentally ill from purchasing firearms and fails to identify or restrict other at-risk people from getting access to guns. Instituting temporary bans on people who have been placed on emergency psychiatric holds or temporary psychiatric detentions could help prevent or lower gun suicides, she said.

Gun control advocates said laws that include waiting periods for gun purchases and "gun violence restraining orders" could also help curb gun deaths.

"Access to a gun during a period of crisis is often the difference between life and death," said Amanda Johnson, a volunteer with the Texas chapter of Moms Demand Action for Gun Sense in America whose sister killed herself. "We can prevent many of these deaths by making sure that law enforcement officials and family members are empowered to make it more difficult for family members to harm themselves with guns."

The National Rifle Association did not respond to a request for comment.

Still grieving

John Beerman, a minister with the Unity Church, continues to grieve for his daughter.

After talking to the detective who investigated his daughter's death and the gun shop that sold her the gun, he still can't believe how easily she obtained it.

He thinks the 4473 form and background check should be strengthened to include more disqualifiers involving psychiatric treatment.

His daughter had gone to Grand Canyon University in Phoenix, Az., graduating early after receiving a full scholarship. She'd had dreams of being a psychologist.

In college, her symptoms worsened, he said. She later moved to The Woodlands and began to isolate herself. She started threatening suicide and sometimes became abusive, he said.

Family members tried to get her into mental health clinics and staged an intervention around Thanksgiving. Soon after she arrived at the hospital, she talked her way out, he said.

She loved being outside, being in nature, meditating and studying human nature, he said. She loved to laugh, to joke and to listen to music.

"The world wasn't there for her," Beerman said. "The people of the world weren't giving her what she felt she needed. I tried my best to love her as much as I could and nurture her as much as I could."