An Arizona couple that has been charged with the shooting death of their 9-year-old son to death originally claimed the boy’s toddler brother had shot him accidentally after he picking up a loaded gun left on a bed in the family’s Phoenix home.

According to the New York Times, Wendy and Kansas Lavarnia were charged with first-degree murder and hindering proseuction on Tuesday after their son died of injuries sustained by a gunshot wound the day before. The parents had already been in custody since police responded to the shooting scene: The mother was charged with child abuse for leaving her children unattended with a weapon, and the father was charged with unlicensed possession of a firearm.

When police initially responded to the scene on Monday afternoon, Wendy Lavarnia told them that she has left a loaded and unholstered 9-millimeter handgun on a bed where her 2-year-old and 4-year-old children were sitting, according to AzCentral.com. She said the two-year-old picked up the gun and pulled the trigger, accidentally shooting her nine-year-old son in the head. Lavarnia reportedly admitted that she had allowed the toddler to play with the gun in the past when it was not loaded.

Phoenix police reportedly began to question the parents’ story when it became clear that one or both parents had cleaned the home before calling 911.

“Significant efforts were made to scrub the house clean and remove evidence while this young boy lay shot and dying,” Phoenix Police Department Chief  Jeri L. Williams reportedly said at a news conference on Tuesday. “This investigation will continue while justice is brought about.”

Mr. Lavarnia also appeared to have a gunshot wound on his arm that Williams reportedly characterized as “suspicious,”  and said that it appeared as though he tried to conceal it.

Mr. and Mrs. Lavarnia are in jail on a $1 million bond, and their three surviving children are in the care of Child Protective Services.

Photo: Maricopa County Sheriff’s Office