DALLAS - 911 tape captured the murder of a Dallas mother.
Sources who have heard the tape tell News 8 it will haunt them forever. They say you can hear Deanna Cook dying.
Cook called 911 from her home on Friday as she was being attacked.
Sources tell News 8 you can hear her screaming for help. Her sister, Karletha Gundy, overheard part of the 911 recording while at DPD headquarters.
“I could just hear how loud she was screaming," Gundy said. "I couldn't hear what she was saying, but I know she was screaming for her life."
Multiple Dallas police sources told News 8 you can hear Cook begging and gasping for help.
In the background, you can hear her alleged attacker, her ex-husband Delvecchio Patrick, saying he's going to kill her. She even calls him out by name.
The call lasts 11 minutes before the line goes dead.
"My thought is, I just think something more could have been done," Gundy said.
News 8 has learned officers in the field knew only that they were going to a domestic disturbance call, and few details were provided to them. In fact, sources also tell us, the operator never relays that Cook is being attacked.
The officers arrive at the home, knock, and leave when there's no answer.
“If they could have kicked the door down, maybe she could have been saved," Gundy said.
The family said on Sunday they called 911 again, because water was pouring out of Cook's home and all the doors were locked. They wanted an officer to check the house.
“The lady said, 'Before we can send an officer out to check, you need to call the hospitals and the jails,'" Gundy said.
The family knocked down the door themselves. Cook's own daughter found her body.
The 911 operator defended herself in an interview with the Dallas Morning News.
"I can say that it's obvious that there was an active disturbance taking place, the screaming and things like that, so I can't say that I knew what was going on, other than there was a disturbance," the operator said. "Obviously my prayers go out to her family, because that's just a terrible situation."
The Dallas Police Department is investigating to see if there was a communication failure.