How did the Sheats family get from there to here?
Credit: Source: Christy Byrd Sheats/Facebook

Christy and Jason Sheats were longtime loves from Alabama, raising their two daughters in a suburb of Houston, on the day Christy decided to load a five-round, .38-caliber revolver and open fire on her family.

She killed daughters Madison, 17, and Taylor, 22, on June 24, as Jason watched in horror, authorities said. Police then shot Christy dead in the street near her kids’ bodies outside their home in Katy, Texas, after she refused to drop her weapon.

How did the Sheats family get from there to here?

Authorities know Jason had announced his desire for a divorce the day of the shooting, after years of a crumbling marriage, Fort Bend County Sheriff Troy Nehls told PEOPLE.

Authorities know that, according to Jason, Christy had attempted suicide three times and had been treated at multiple mental health facilities in the last four years; and that she fought with Taylor and Jason the day of the shooting.

And authorities know that Christy began to “spiral” after her grandfather’s death in 2012, months before her mother died, and Jason believes she killed their children as a way to make him “suffer,” according to what Jason told investigators.

But there was no history of Christy being violently unstable, Nehls told PEOPLE. He said that, on that Friday, as the family gathered in their living room before Christy unexpectedly opened fire, Jason expected they would discuss the divorce.

She pulled a gun instead.

‘Her Parents Had a Really Beautiful Story’

Christy and Jason met when they were younger. “And they just knew they were going to be together,” Austin Crockett, Taylor’s childhood friend, told PEOPLE.

They apparently grew up not far apart from each other: Christy was a native of Decatur, Alabama, according to – a 15-minute drive from Trinity, where Jason had lived and attended high school, according to one of his Facebook friends.

“Her parents had a really beautiful story,” Crockett told PEOPLE. “And they would always tell the story [of their meeting] and they were [Taylor’s] heroes.”

Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter.

Christy appeared to be a devoted mom, too, according to one friend.

“She loves her daughters,” friend Catherine Knowles told PEOPLE soon after the shooting. “I have no idea what could possibly make a mother who loves her daughters as much as she did – what could cause a person to snap?”

“The part of Christy that I knew was a very kind, loving mother,” Knowles said. “Within 20 seconds of meeting her, we were talking about her being a mom. That was her mission in life, that was her everything – her two daughters.”

A ‘Very Difficult Time’

By late June, authorities say the Sheats marriage had soured and Jason said he wanted a divorce. The same day as the shooting, his birthday, he told Christy, “This would be the last birthday that you are going to ruin,” Sheriff Nehls told PEOPLE.

Things took a turn in 2012, Jason told investigators, Nehls said.

“He [Jason] believes she had a very difficult time dealing with the death of her grandfather,” Nehls said. Christy’s mother died two months later.

In the four years since, Christy sought treatment at three mental health facilities, Jason told authorities. The family also started a pattern of service calls for authorities to their home, including three calls about Christy’s suicide attempts, Nehls said.

Jason told authorities Christy was taking several medications for depression and anxiety, but Nehls told PEOPLE he did not have any information about her medication regimen or how it might or might not have affected her stability.

The day of the shooting, Christy had an argument with Taylor and wanted to ground her, to keep her from seeing her fiancé, Nehls said. Jason disagreed with that decision. He and Christy discussed divorce that day, too, Nehls said.

Within hours, both daughters and Christy were dead. Jason, a witness, pleaded with his wife not to shoot, according to 911 audio. “I promise you whatever you want,” he can be heard saying on one call.

Jason, who was “obviously in a lot of shock out at the scene, spoke at length with authorities a few days later, Nehls said. He has declined, through authorities, to speak publicly.

On Wednesday, he resumed posting on Facebook, sharing a compilation of photos of his family: him and his daughters together, smiling.

Christy was not included.