 -- The grandparents of the lone teenage survivor of a Houston massacre are "in awe" of her courage that allowed her to call the police despite being wounded in the head and warn them that the shooter had left to find her grandparents and shoot them too.

Cassidy Stay, 15, played dead after Ron Haskell allegedly tied her up along with her parents and four other children. He is charged with capital murder for allegedly shooting all seven in the head. Only Cassidy survived.

“We are in awe of her bravery and courage in calling 911, an act that is likely to have saved all of our lives. She is our hero,” Cassidy's maternal grandfather Roger Lyon said in a statement. Lyon and his wife were Haskell's next target, police said.

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“More information will be forthcoming in the days ahead about her heroics, but right now we want to concentrate on getting her well,” Lyon said.

Cassidy is expected to make a full physical recovery, he said.

Aubrey Westwood, Katie Stay's sister, posted on the GoFundMe page that has been sanctioned by the family saying that her niece was able to escape to a neighbor's home in order to make the call to police.

"Without the grace of God in sparing the life of my very brave 15-year old niece, there could have been a dozen or more victims and the suspect may not be in custody. We commend her, I count her a hero and we are grateful to have everyone else with us today," Westwood wrote.

The teenager's phone call prevented additional carnage, police said. "The surviving victim was able to provide first responders with information regarding Haskell’s whereabouts," the sheriff's office said. They blocked Haskell's car by ramming it with a pair of armored vehicles and he surrendered after a three hour standoff.

Haskell is scheduled to appear in court today.

Cassidy's paternal grandmother Joyce Stay, who lives in California, spoke with her granddaughter on the phone after Cassidy was taken to the hospital, she told KABC.

“I said I was so sorry about everything that’s happened, but I’m so thankful you’re still here with us,” Joyce Stay said. “But she said, ‘My mom and dad are in a better place.’”

Her parents, Katie and Stephen Stay, were killed in the shooting.

Family friend Corinne Attaya said news of the tragedy feels like a bad dream.

“It’s mind-numbingly awful,” Attaya said. “My heart aches for [Cassidy]. It aches and breaks every time I think about it.”

Joyce Stay said her son and daughter-in-law were known as a warm, loving couple.

“If they could do anything to help anybody else they would go out of their way to help other people,” she said.

“Katie and Stephen loved each other totally. Just wonderful. I mean, so committed to each other.”

According to court testimony on Thursday, Haskell first went to the victims’ home posing as a FedEx delivery man. He had previously worked as a FedEx driver, employed by an independent contractor.

Cassidy Stay answered the door and turned away Haskell – who had been married to her mother’s sister – authorities said. Haskell left, but came back and kicked in the door, according to the court statement, tying up the children and waiting for their parents to return.

He allegedly tied up the two adults and forced everyone to lay facing the ground, the court was told.

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While the family lay bound, Haskell asked where his wife was, prosecutors said. When they said they didn’t know, Haskell allegedly shot every member of the family in the back of the head. Cassidy Stay, suffering from a fractured skull when a bullet grazed her head, faked being dead until Haskell left, authorities said.

Haskell only made it about four miles on his mission for vengeance, authorities said. Officers trailed him in the low-speed chase, using spike strips to slow his car. His car came to a rest in a suburban cul-de-sac, with trucks wedging in front and behind his car to ensure that he couldn’t move.

The standoff lasted more than three hours. Authorities spoke with the man by cell phone as darkness fell over the scene.

At about 10 p.m. local time Haskell exited the car and surrendered.

Haskell has previously been accused by relatives of abuse and threats, according to police records obtained by ABC News. Haskell's mother, Karla Jeanne Haskell, told police in San Marcos, Calif., on July 3 that she wanted a restraining order against her son after a ferocious argument that began when she told him that she was in contact with his ex-wife, court documents state.

She said that he forced her into the garage and tied her wrists with duct tape before taping her to a computer chair.

"He yelled at me and twice placed his hands around my neck trying to choke me and caused me to pass out," Karla Haskell, 61, said, according to the court documents. "He told me he was going to kill me, my family and any officer who stops him. He hid my telephones. I was taped up for four hours."

There is no record of Haskell being arrested for the alleged assault on his mother.

Police reports in Utah indicate that Haskell's ex-wife Melanie Kaye Haskell was also the victim of violence. Ron Haskell was charged with domestic assault on June 5, 2008 after his wife called the police saying that he had dragged her out of their bedroom by her hair and repeatedly punched her in the head.

The Logan City Police Department report states that she then decided to go and sleep in their children's bedroom, but he followed her in there and pulled her out of the room by her hair once more, continuing to punch her in the head.

Police booked him on domestic assault and domestic violence in the presence of a child because the couple's children, aged 3 and 5 at the time, were present. He made bail and was released five hours later. It's not clear how the charged was adjudicated.

The final issue that the Logan City Police Department was involved in was a protection order violation. His wife had been awarded a protection order in July 2013 and on Oct. 8, 2013, she called in a protection order violation because he had showed up at one of their children’s' schools.

The wife filed for divorce months later – on Valentine's Day.

Jonathan Ricks, a family friend, says he remembers Katie Stay discussing her sister’s troubled marriage.

“Katie had told me on one occasion how her sister was leaving an abusive relationship,” Ricks said.

Tom Stay, Stephen Stay’s father, told KABC that he never expected this sort of trouble from Haskell.

“He was in a good home, brought up in a good family, they taught him the gospel and he understood what was right and wrong,” Tom Stay said. “And he was a good boy, but how he changed … you just don’t know.”

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