BROKEN ARROW, Oklahoma - A three-year-old Broken Arrow boy is dead and his foster mother is charged with his murder. Investigators said he died Sunday after suffering massive head trauma.

Police said the boy's foster mother brought him to the hospital almost a week ago claiming he fell off the couch and hit his head on the floor.

Investigators said her story just didn't match up and she's now charged with child abuse murder.

It was inside a home on South Elm Place in Broken Arrow where police said three-year-old Andrew Prior suffered such massive head injuries that he died five days later.

Court records show his foster mother, 25-year-old Mallory Krajian claimed he fell off the couch and hit his head, but police aren't buying that story.

“Some of the other injuries were consistent with the charge. It is not just about a fall and bumping a head, it's about bruising, and other parts of the body, and that sort of thing,” said Major Mark Irwin with BAPD.

Two other foster children lived in the home - a four-year-old girl and six-year-old boy.

Investigators said the four-year-old girl was also being abused - and along with Mallory - police arrested her husband, 44-year-old Peter Krajian for child abuse.

“She was a very friendly-type person. He was quiet and standoff,” said neighbor Floyd Allen.

He said the children often came to his house for visits.

“It's not only upsetting its guilty,” Allen said, feeling like he could have done something more. “I can't change it now, but imagine the guilt you'd have, to think that I might have been able to prevent that.”

Broken Arrow police said they haven't had any previous issues with the couple who had been fostering Andrew since last summer.

“It's unfortunate when a child passes away and one of them is injured. It can happen anywhere,” Irwin said.

Mallory never admitted anything to police, and they wouldn't get into too many details, but the affidavit shows Mallory suggesting to police that one of the other children might have caused Andrew's injuries.

Police said the investigation is still very much underway - with almost a dozen witnesses interviewed - and there could possibly be more charges filed.

As for the other two foster children living in the home, police said they have both been placed back with DHS.

Mallory is being held on a $250,000 bond and her husband, Peter, is being held on a $25,000 bond.