An Irving mother who believed "demons told her to sacrifice her son" has been arrested and faces a charge of capital murder in the death of her 8-year-old child.

Irving police responded to a call about an unconscious person at 7:26 a.m. Sunday in the 2600 block of Peach Tree Lane.

When officers arrived they found the 8-year-old boy dead, police said. He was identified by the Dallas County Medical Examiner as Joevani De La Pena.

The boy’s mother, Tisha Sanchez, 30, was arrested.

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"The motive for this murder is still unclear however the investigation is progressing," Irving police said in a news release.

According to the arrest warrant, a relative told police that Sanchez told her that "demons told her to sacrifice her son" and that "she needed to forgive her."

Police said relatives told officers that the boy was suffocated with a pillow.

Dallas County Jail records show Sanchez also is charged with resisting arrest and assaulting a public servant.

Those charges stem from an incident in November when police were called to a clothing store off State Highway 183 about a mother who was dragging her son around the store, police said.

Officers decided she was in need of mental help and took her to Parkland Memorial Hospital in Dallas, police said. It wasn't clear how long she spent in the hospital before being released.

Child Protective Services was notified and conducted a full investigation after the incident, said spokeswoman Shari Pulliam.

"We did our due diligence," Pulliam said.

She said the boy was interviewed and said he had a "great mom," and CPS closed its investigation.