TULSA, Oklahoma - Tulsa Police arrested three people in a case of child abuse that's left a 2-year-old boy on life support.

Police say he has a severe brain injury.

Monday, police said a woman went to the Hillcrest Hospital ER with the 2-year-old, unresponsive, and then left without explaining anything.

Corporal Mark Kraft said, “The child was obviously very injured and she handed the baby off and said ‘I need to go move my vehicle, I'm parked right out front.’”

But the woman left the hospital and the child behind.

Police identified the woman as Dominick Smith, 31, who, along with Johnny Jones 42, was watching the child when the little boy was severely injured.

"A serious brain injury is the main concern right now. We don't know exactly how those injuries were caused. We interviewed everybody involved but got inconsistent stories about what the injuries the child had,” Kraft said.

Police backtracked to an apartment complex where Smith and Brown said they were keeping the child.

Child crisis detectives believe something happened there to cause the brain injury - then the child was given an overdose of cold medicine.

They found Jones at the complex and took him in for questioning.

More police legwork took them to the home of Keyshawn Brown, 23, the child's mother.

Kraft said, "We learned that mom has a history of leaving the child with whoever she can find for days on end, but this time she left it with the wrong couple I guess."

Police ended up arresting all three - the mom for child neglect, Jones for neglect, and Smith for neglect and abuse.

The child, according to police, won't survive.

The mother told police she last saw the child three weeks ago.

Police said some older children were in the apartment when the abuse happened; they hope to get some information from them.