Police have arrested an Arizona mother whose 1-year-old son died after allegedly being left alone for eight hours while she went to work.

According to AZ Family, officers were called to a Phoenix home on July 14, following reports of an unresponsive child. There, they were met by mother Donielle Joyce King, 32, who led them to her unresponsive baby lying in a bed. The child was pronounced dead at the scene.

Court documents stated that King confessed that she had left she her son home alone when she went to work at 6:30 a.m. She explained that she had dropped her other four children off at daycare but the 1-year-old “had open sores so he was not eligible for daycare,” police said.

The mother also claimed a friend was supposed to babysit him but didn’t show up.

King said she returned home from work at 4:15 p.m. to find her son unresponsive on the bed. She reportedly performed CPR while her daughter called 911.

Police said that bruises on the toddler’s ankles and face contradict the mother’s story and suggest that the baby was abused. Reports obtained by news station revealed that King was arrested on child abuse charges in 2016.

It remains unclear how the 1-year-old died.

The other four children are in the custody of the Department of Child Services, according to WPMT. Facing child abuse charges, and is barred from having contact with her children or anyone else under the age of 18.

“If you are a threat to a one-year-old, you may well pose a significant, if not greater, threat to older children,” a judge said during King’s preliminary hearing, according to AZ Family.

King remains behind bars on a $50,000 bond.

[Featured image: Donielle Joyce King/Maricopa County Sheriff’s Office]