KYLE, Texas (KXAN) — A mother is accused of stabbing her 5-year-old daughter to death at a home in Kyle on Thursday, in what Sheriff Gary Cutler called probably the most horrific case in the history of Hays County.

The mother, 24-year-old Krystle Villanueva, has been charged with capital murder for the death of Giovanna Hernandez, who was mutilated, police say.

At 12:51 p.m., Hays County Sheriff’s deputies received a 911 call reporting an aggravated assault at a house on Willow Terrace in the Green Pastures subdivision of Kyle.

Deputies arrived and found 58-year-old Eustorgio Arellano-Uresti in the driveway with multiple stab wounds. A 10-inch-long knife was found in his back left pocket. The man said his daughter-in-law, Villanueva, stabbed him and was alone inside the home with a child.

Hays County SWAT team was called and entered the house, finding Villanueva without any clothes on, having just got out of the shower. She was detained and removed from the house. The SWAT team then found Hernandez dead in a bedroom, according to a police affidavit.

Arellano-Uresti told officers that at around 11 a.m. he walked into the kitchen to make lunch when he saw Villanueva take a knife to a back bedroom. He then heard the child crying. Authorities believe at this time Villanueva was stabbing her daughter. The mother then returned to the kitchen and began stabbing her father-in-law in the back and forehead as he tried to grab the knife, the affidavit continued.

The man was taken to Seton Hays Hospital, treated and released.

He told police that Villanueva used drugs. Her sister told officers that in late 2015 the mother was admitted to a facility in Buda for treatment of substance abuse, including marijuana, crack and meth. While in treatment, she was diagnosed with bipolar disorder, schizophrenia and ADHD, the affidavit stated. Police say they do not know exactly if drugs or alcohol were involved in the death until toxicology results are returned in 4-6 weeks.

A witness said that after the man exited the home, he saw Villanueva standing outside with a firearm, trying to use it. Arellano-Uresti later told officers that the shotgun kept inside the home was unloaded.

Villanueva has also been charged with aggravated assault, a second degree felony, for injuring Uresti. Sheriff Cutler said Villanueva had only been living in the house for a week. “This is one of the worst cases I’ve ever seen,” he said. “The suspect has had minor issues with law enforcement in the past, nothing major.”

When asked why it took so long to get to the girl after police were called, Cutler said — based on the information received from Uresti — the decision was made to call out the SWAT team before entering the house.

Villanueva remains incarcerated in the Hays County Jail charged with capital murder and aggravated assault.

Friends of girl’s parents speak out, hoping to understand

Sabrine Sifuentez and Stacey Carrizales tell KXAN they have been best friends with Villanueva for years. They say she was like a sister to them, and so, Giovanna was like a niece.

“She was just a precious little girl. She didn’t have a care in the world. She loved to play tag. She loved a lot of things,” cried Sifuentez. “I just can’t believe she’s gone.”

“She was always smiling. She was always running up to us and wanting to play, singing and dancing,” added Stacey Carrizales. “She was a very compassionate, very caring little girl.”

The friends say they never thought Villanueva could do this to her little girl. When they found out about the circumstances of Giovanna’s death, the two broke down. “That’s not Krystle. That’s not her. It’s not,” said Carrizales. “We’ve known her so well that it’s not her. It’s not her character.”

“She loved her,” the women cried, saying Giovanni meant the world to Villanueva. The women said Villanueva wasn’t perfect. They say she struggled for years with drugs.

“She went to a rehab. She did a 90-day program and she came out good. She was doing good. She had a job,” explained Sifuentez. “She tried to get help. I don’t know if she just relapsed, or I really can’t say what happened.”

Carrizales said the last time she heard from Villanueva she wanted her help trying to get a job. “She reached out to me. She wanted me to get her a job and help her out. I said ‘yes, but you know, you have to be straight,’ and she said that she was straight.”

“[Villanueva] just went through a lot of things and it’s very unfortunate that it went this way, this route,” she added.

Addiction, her friends say, is serious. “It’s no joke. I just really want to let people know and encourage people to reach out to anybody that’s really going through that struggle because it is serious. Please don’t ignore them,” said Carrizales.

“Just listen to what they have to say. Hear them out,” said Sifuentez. “You never know whose life like you could be saving.”