Girl, 6, Finds Parents Dead in House, Rushes to Tell Older Sister, 17, Unaware She's the Shooter: Police

The investigation began on February 20 when the Carroll County Sheriff's Office received that 911 call from a teen saying that her mother Kristin Brock, 41, and stepfather James Brock, 45, had been shot in the family's home, according to WSB's reporting at the time.

"From the very moment the 911 call was received, a relentless investigation began," said Carroll County Sheriff's Office spokesperson Ashley Hulsey in a press conference after the arrest of Sarah Grace Patrick, 17, the very teen who made that call.

Now, Patrick is being charged as an adult and facing two counts of murder and two counts of aggravated assault for the deaths of her mother and stepfather.

Patrick was with her biological father when they were advised by authorities that the investigation was pointing toward the teen, per Law & Crime -- and it was her father who helped her turn herself in Tuesday morning.

"We feel confident that she is responsible for their murders," Hulsey said in the press conference later that afternoon. "She turned herself in because we notified her that we had warrants for her arrest."

At the same time, Hulsey said that the investigation is far from over and she's not ruling out the possibility of more arrests as they're not certain if the alleged suspect carried out the crimes alone.

"Our team has sifted through mountains of physical and digital evidence and collaborated with the FBI and GBI crime lab," she said, which included the teen's tearful speech at her mother's funeral, as noted by The New York Post -- a moment investigators suspect might have been a ploy to cover her tracks.

"It's very possible others are involved as well," she told reporters. "We are still working with her diligently, our investigators have been speaking with her." Police have also not yet been able to determine a motive for the shootings

"We don't know what goes through the mind of a child who wants to harm their parents," Hulsey added. "She's 17. She's kind of been out on her own. She's lived with different family members and moved all over the place."

When asked if Patrick had tried to conceal what happened in February, Hulsey noted, "Considering that she didn't just immediately tell us what happened, yes. But who knows what's going on in a young person's mind like that."

Because their suspected shooter was so close to the victims, Hulsey said that it took five months of investigating for police to feel confident enough they had this right to move toward warrants. They wanted to be as certain as possible they arrest the right person.

One heartbreaking twist in the story is the fact that it was Patrick's younger sister, 5 at the time of the murders, who first found the bodies. Police at the time had determined this younger daughter had been in the house at the time of the shootings, but was unaware it had happened.

"Smallest daughter found them and then she came and told Sarah and Sarah made the 911 call," Hulsey said in Tuesday's press conference. The younger daughter had no idea that her older sister was the alleged shooter.

"She is probably the saddest victim in all of this," Hulsey said of the younger sister, noting the trauma this young child had to endure, and will have to live with.

Though there were no signs of forced entry at the time, one door was slightly ajar and the fact police were unable to find the murder weapon led them to quickly rule out suicide in the February deaths of James and Kristin Brock.

The had recently joined a new church and were well-liked in their community, per CrimeOnline.

Tasha Meza, who had invited them to their new church, said of the couple at the time of their deaths, "Kristen was bubbly and fun and she loved hugs. She never met a stranger. And James, he was a comical kind of guy. He would always crack jokes and always say something to make you laugh."

James was also a survivor, with the investigation uncovering that he'd been dealing with years of health issues, including multiple medical procedures.

"According to his family, he had a lot of heart trouble; he had numerous heart surgeries; I believe he may have been waiting on a heart transplant at some point," Hulsey said. "To have his life cut short, when he was given so many opportunities to live, to me that's a big takeaway from this story."

The biggest takeaway for her, though, is "that a mother and stepfather will never be able to raise their children and the little girl that was in the home."

The couple is survived by their seven children, who had been combined into a blended family at the time of their deaths.

If convicted, Patrick faces up to life in prison without the possibility of parole.