Brandy Vela's sister can't remember a time when she wasn't bullied

After months of online torment, a Texas teen fatally shot herself in front of her horrified family. Could she have been saved? Subscribe now to PEOPLE, or pick up this week’s issue, on newsstands Friday, for more on this story.

Brandy Vela’s sister can’t remember a time when she wasn’t bullied.

“People always talked about her,” Jackie Vela tells PEOPLE. “But in April of this year, it got really bad.”

So bad that on Nov. 29, tragically, 18-year-old Brandy fatally shot herself at her Texas City, Texas, home in front of her family. Police have since opened a criminal investigation to determine if she was the victim of cyberbullying, and her family has joined broader efforts to prevent such behavior online.

Jackie and her family say bullying is indeed to blame, though they always thought Brandy “brushed it off and didn’t care.”

And then Jackie received a text message from Brandy just hours before her death: “Guys, I love you so much, please remember that, and I’m sorry for everything.”

Jackie jumped in her car, made the three-minute drive to her childhood home and found Brandy leaning against her bedroom wall with a gun to her chest.

“I started yelling, ‘Brandy, stop, talk to me!’ ” Jackie recalls. Her family also rushed home, but all their pleading couldn’t convince her to put down the gun.

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Brandy Vela
| Credit: Vela family

“I can’t do this anymore,” Brandy said, according to her family. “I’m tired. I’ve come too far not to do it.”

She pulled the trigger.

‘What They Did Wasn’t Just Bullying’

On social media, Brandy’s tormentors made up fake Facebook accounts and posted about her weight and looks, her family tells PEOPLE. Even when the Facebook pages were deleted after they reported them, it was just a matter of days before a new one was created.

The profiles had Brandy’s name and photo and said she would “offer sex for free,” Jackie says.

“It didn’t stop,” she says. “What they did wasn’t just bullying — it was stalking”

Brandy Vela - 3
The Vela family
| Credit: Vela family

“They would say, ‘I’m a slut and I’m a hoe. Anybody hit me up,’ ” Jackie explains. “It also had her phone number, so she would get text messages and phone calls all the time. It kept her up at night.”

Brandy’s school, Texas City High School, acknowledges that she came to them about harassing messages before Thanksgiving but that there was nothing they could do.

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“Our deputy investigated it, and the app that was being used to send the messages was untraceable,” the school said in a statement to PEOPLE. They “encouraged [Brandy] to change her phone number.”

Meanwhile she would send her family screenshots of the cruel messages, but they were never able to figure out who the person was behind the phone number. Then it was too late.

“She was frustrated by it,” Jackie says, “but we didn’t know how much it really affected her until now.”

“It’s just really heartbreaking,” she says. “My baby sister is gone.”