CONROE, Texas (KTRK) -- ABC13 obtained exclusive video of the Lakewood church shooting suspect just hours before she allegedly entered the building with an AR-15 and opened fire.
The mother, who had her 7-year-old son with her at the time of the shooting, had a long-documented history of mental illness, yet she legally purchased the gun.
Hypothetically, if a red flag law was in place, Genesse Moreno could've been denied that gun she used to carry out the shooting here at Lakewood church.
Chilling new video shows Moreno outside her Conroe home just hours before she took her 7-year-old son and two guns to Lakewood Church.
A second video shows the trunk of her car popped open. The vehicle is backed all the way up to her garage, and a tarp is cutting off the view of anything going in and out.
SEE MORE: Conroe PD tight-lipped on reports involving Lakewood shooter after neighbors claim calling for years
The 36-year-old allegedly entered the nation's largest church on Sunday wearing a trench coat. One can be seen on her arm in the surveillance.
According to Houston police, Moreno's son was by her side when she entered the church and shot her AR-15 into a crowd of people.
Her son was shot in the head and continues to fight for his life.
Police said Moreno was killed by two off-duty police officers during a shootout. Walli Carranza, Moreno's ex-mother-in-law, said the 36-year-old was diagnosed with schizophrenia, and her battle with mental illness was thoroughly documented.
"She threatened my son's life and my grandson's life, and she put my grandson in harm's way for seven years, not just now. But under all of that was a woman who just needed treatment," Carranza said.
Carranza said she believes Sunday's shooting could have been prevented with red flag laws.
"Whether it involves extreme risk protection orders, also known as red flag laws or background checks on all gun sales, which I think could apply in this case as well when we are looking at the Houston shooter and many other cases, you know those are two pieces of legislation, we know we need in place, and there are others too," Nicole Golden, the executive director of Texas Gun Sense, said.
Golden said they've long been working with lawmakers at the capitol to pass a red flag law.
Twenty-one states already have, and she says data backs up the benefit.
"We know in some states that have put them in place, they've seen reductions in homicides and suicides," Golden said.
What was going through Moreno's mind in the days and hours leading up to the shooting is still a mystery.
But, Golden said, if she was indeed sick, she should've never been sold that gun.
"Those policies can give tools to family members when they are seeing extremely dangerous behaviors, threats being made by a loved one in possession of a firearm. It may have applied in this case. We know it could have applied in other cases," Golden said.
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SEE MORE: 'Why she went to Lakewood, I have no idea,': Ex mother-in-law of shooting suspect speaks to ABC13