A Texas mom has been arrested in connection with her newborn daughter’s death — after trying to blame her 3-year-old son for killing the girl.

Halle Marie Murry, 25, was nabbed over the weekend on a capital murder warrant in the death of her 6-week-old daughter, Acelyn Lailani Rogers, on Jan. 14, the Fort Worth Star-Telegram reported. Acelyn died later that same day of traumatic head injuries.

The mom initially told cops that she awoke to find her son standing over Acelyn’s lifeless body and later insisted to a hospital chaplain that the boy has attention deficit disorder and “dropped her,” according to an affidavit obtained by the Star-Telegram.

But a doctor told Murry a 3-year-old couldn’t have caused the baby’s serious injuries — and that’s when her story started changing.

The mom then told police that she woke up and saw Acelyn on the bed and her son standing over the baby while playing with a metal fidget spinner. She suggested the toy caused bruises on the girl’s forehead — and that the boy may have hurt her while trying to pick her up, according to the report.

“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 doctor told the detective that the infant had one of the worst skull fractures he’d ever seen and he didn’t believe a 3-year-old was capable of causing so much damage.

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.

“It wasn’t until after she realized her initial story about how the injuries may have happened were questioned, that she gave inconsistent statements as to what she actually did at the apartment prior to officers securing the scene,” West wrote.

An autopsy determined the Acelyn had multiple fractures caused by repeated blows to the head.

The affidavit said both Murry and her son tested positive for cocaine days after Acelyn’s death. The boy is now living with a relative.

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.