Texas Mom Who Killed 2 Daughters Had a 'History of Mental Illness,' Authorities Say

The Texas woman who killed her two daughters on Friday, before being shot and killed by police herself, allegedly had a history of mental illness, officials say. And she had posted multiple times on social media about her support of firearms.

The Fort Bend County Sheriff’s Office had been to Christy Sheats’ home “for previous altercations” involving Sheats’ “mental crisis,” sheriff’s spokeswoman Caitilin Espinosa tells PEOPLE.

She declined to provide more detail about those incidents.

On Friday afternoon authorities responded to a tragic scene outside Sheats’ home, Espinosa says: The bodies of Sheats’ two daughters, 17-year-old Madison and 22-year-old Taylor, were in the street after they’d allegedly fled from their mother when she began firing her gun inside the home.

Taylor had already been shot once inside and was shot twice again outside, Espinosa says. Madison was shot once outside.

Christy was shot dead by a Fulshear city police officer “before she was able to shoot [Madison] again,” Espinosa says. Both daughters died from their injuries.

(A Fulshear police representative told PEOPLE on Saturday he did not have information on how the department will handle the officer involved in the shooting, and he said no such information would be released going forward.)

While Espinosa says the shooting’s motive remains “unknown” and under investigation, Sheriff Troy Nehls said it was “a family argument that turned into a shooting,” according to the Houston Chronicle.

“We’re still trying to put the pieces together,” Nehls said.

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One neighbor told ABC13 that Christy and her husband had recently reunited after a separation, and that Friday was his birthday.

Christy’s husband, the girl’s father, was at home when the shooting started but was uninjured, according to the Chronicle. He was taken to a local hospital and is “going through a very difficult time,” Nehls said.

Christy was an active user on Facebook, and posted multiple times in recent months to express her enthusiasm for firearms – and her distaste for gun control.

“It would be horribly tragic if my ability to protect myself or my family were to be taken away, but that’s exactly what Democrats are determined to do by banning semi-automatic handguns,” she wrote in March, along with an anti-gun control video.

And in January she posted a meme showing a handgun which made fun of President Barack Obama’s position on gun control. She captioned it “That’s right! #merica.”

Both Madison and Taylor reportedly worked as babysitters. Madison was a rising high school senior, according to ABC13, and Taylor attended Lone Star College, according to the New York Daily News.

The community is reeling from the shooting – and what it must mean for the Sheats family.

“[The husband] loved his daughters,” one family friend told ABC13. “They were like best friends for sure. It crushed him. I know it’s hard for the family.”

A neighbor told ABC13, “All I can say is they are nice people. There’s nothing wrong with them.”

And one of Madison’s close friends told the station she “brought nothing but happiness to everyone she ever met. She was nice to everyone and she wouldn’t have harmed a fly.”

In September, Christy posted on Facebook to celebrate “Daughter’s Day.”

“Happy Daughter’s Day to my two amazing, sweet, kind, beautiful, intelligent girls,” she wrote. “I love and treasure you both more than you could ever possibly know.”