A Texas mom accused of killing her 2 month old daughter - is blaming her 3 year old son for the killing.

Police say that 25-year-old Halle Marie Murry showed up to the hospital in Fort Worth, carrying the 2-month old victim, Acelyn Lailani Rogers

Halle told authorities that her 3 year old son "dropped" his baby sisters and she sustained life threatening injuries. Acelyn eventually died at the hospital.

The arrest warrant reports, “The victim’s mother had been providing information her 3-year-old son caused the injury to the victim."

“She stated how bad her 3-year-old has acted in the past by describing him hitting Acelyn with objects, slapping, biting, kicking and spitting,” the detective on the case, C. West, wrote in the affidavit.

A forensic interviewer and a doctor watched as the boy interacted with a doll that resembled his sister. The doctor said the boy did not “demonstrate the dexterity or force to cause the extensive head injuries,” according to the report.

Murry also gave varying excuses as to why she accessed the apartment where Acelyn died prior to cops being able to secure the scene, West wrote in the warrant.

But the doctor didn't believe Halle. He described the baby’s head injury as “one of the worst skull fractures he has ever seen,” adding, “there is no way a 3-year-old could have caused this amount of damage,” according to that warrant.

The medical examiner agreed and ruled Acelyn's cause of death as traumatic head injuries, and the manner as homicide.

On Wednesday, after documenting alleged inconsistencies in the mother’s account, Murry was arrested Saturday at her workplace on a capital murder warrant and was being held in the Tarrant County Jail. Bail has not yet been set.