According to investigators, the brutal attack took place in front of the couple's 8-year-old daughter.
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Family members continue to question whether the police arrived in a reasonable time frame.
ABC13 submitted an open records request to uncover those response times, but Houston police said they don't want to release that information right now.
In a letter to the attorney general's office, HPD argued that releasing the information could impede the investigation, but Eyewitness News plans to submit a counter-argument.
Michael Simpson Jr. is currently in jail. He's facing charges for the murder of his wife and for an aggravated assault on his daughter.
"My daughter's body was stabbed over 60 times," Addie Farrell, Robin's mom, said.
Simpson Jr.'s gruesome attack on his wife Robin happened on Nov. 1, according to police.
Investigators said he stabbed her to death inside their home on the south side of the city.
ORIGINAL STORY: Man stabbed wife to death, tried to take his own life while 8-year-old child was home, HPD says
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"I asked the coroner for pictures before they had to cremate her because my daughter's body couldn't be embalmed because he destroyed all of the arteries, and I wanted them to know just what he did," Farrell said.
Police said the couple's 8-year-old watched as her father stabbed her mother over and over again.
Now, the girl is in Philadelphia, where the family is from.
"She still wakes up about that time that it happened because it is here in her head, and she is here with her family, and we are all supporting her," Farrell said.
After stabbing Robin, investigators said Simpson Jr. stabbed himself, but he recovered.
On scene, police said they did not enter the home until Robin's daughter ran out and said, "Daddy is stabbing Mommy."
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The family is questioning whether there was some kind of delay in police response.
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"That is what we are talking about, why the cops were still standing outside when she was getting stabbed to death," Farrell said.
The family is terrified Michael Simpson Jr. could post bond, which was set at $340,000. He will have to put up 10% of that to be released.
"My niece is fearful of her dad getting out of jail, fearful. She tells me every day, I pray my dad never gets out of jail," Malaina Hatcher, Robin's sister, said.
Simpson is due back in court on Jan. 11.
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