An Oklahoma mom thought it was safe to leave her baby son in the care of her boyfriend while she went to work over the weekend, but she was heartbroken when she returned home to find the child hurt and unresponsive.

According to News 4, the mother was at work on Sunday when she received a call from 29-year-old Phillip Howard, who was babysitting her one-year-old boy, Kaleb.

The mom immediately contacted police and rushed home to her child, where she found him with serious injuries. 

Del City Police Major Ted Kleber told News 9:

“There was a large swelling, about the size of an apple by the time we got there. It was increasing in size on the right side of his head. So, probably from a brain bleed.”

Baby Kaleb was pronounced dead just 30 minutes later. 

Howard immediately came up with a story to explain the injuries. He claimed the child's death was a complete accident, Kleber said:

“His story was, he woke up, went to see the child, changed his diaper, was going to take it into the kitchen to feed it. Along the way, he trips over a rug, falls to the floor, landing on the baby on the floor, and says that's how the baby died."

But police said that the boyfriend's story wasn't consistent with the baby's injuries.

Kleber explained:

“Not a strike or anything like that, but this is a twisting of the leg."

His story also didn't explain why he failed to contact help until hours after the incident occurred. Howard was intoxicated when officers arrived at the scene. 

The boyfriend has since been arrested and charged with child neglect resulting in the death of a child, New 4 reports. Authorities also found drugs in the home at the time.

Police said there may be more charges to come.