TULSA, Ok - Tulsa Police arrested a woman accused of stabbing her 11-year-old daughter, leaving her 9-year-old daughter for dead, and taking off with her 8-year-old daughter, causing an Amber Alert.

The 8-year-old girl wasn’t hurt, but her 11-year-old sister remains in critical condition.

Police said the mother, 39-year-old Taheerah Ahmad, admitted to trying to kill two of her children.

Police got the call about 12:30 Tuesday afternoon that a car matching the suspect vehicle – a black Lexus SUV - was parked in a parking lot in the Tulsa Arts District, and the missing girl was inside.

The missing 8-year-old girl was playing around the sunroof, which is what caught the eye of two women – Emily Wilson and Anastasia Brazendeh - walking by.

“The little girl was playing up around the sunroof, and that made us question it. She seemed happy and just being a little girl, standing up at the sunroof, playing around, climbing out, and the woman was just laying down in the backseat,” Wilson said.

Both women, both mothers, said they watched the Amber Alerts and suddenly realized it matches the vehicle description.

“That's a black SUV, Lexus, matches the description of the Amber Alert. The little girl, wearing the orange peach dress, poofy hair like they described, and we’re like, let's just call to be safe. Let’s just call even if it's not,” they said.

Police said the girl was fine as she was led away by officers.

Ahmad was taken downtown, photographed by police and questioned about the events in the house 16 hours earlier.

Police said two girls – the 11 year old and the 9 years old - were bound and gagged. The 11-year-old girl was stabbed, and both were left there with the house on fire.

Child crisis detectives said Ahmad told them what led to the incident.

“She admitted to being upset with the older two children for the way they were reading their books, so she bound their hands with duct tape,” Corporal Mark Kraft said. “She admitted she stabbed the child 50 to 60 times, that's what she said, and then hit her in the head with a pickax two or three times.”

As Ahmad remains in custody, her oldest daughter is in extremely critical condition; the two other children are now with DHS.

Police had every patrol officer and detective working the case but had no idea of the location of the child and her mother until they got a call from the two women who paid attention to the Amber Alert.