LEAVENWORTH, KAN. - Leavenworth, Kansas police have made a second arrest in the death of 4-year-old Gabriel Rivera. On Monday, police arrested the boy's mother, Monica Rivera, 28, and will face criminal charges.

Earlier in October, police arrested Jason Jones, 33, Monica Rivera's live-in boyfriend in connection with the death of Gabriel Rivera. Police said Gabriel died Sunday, Oct. 4, after being brought to a hospital with serious injuries. The boy died at the hospital. Leavenworth police investigators arrested Jones for felony murder following the child's death.

Police believe this is a clear case of child abuse at the hands of a man who has been in trouble with the law before.

Jones was released from prison last November after serving more than two years for aggravated assault in Atchison, Kan.

Soon after his release, neighbors said he moved into a house on Tonganoxie Road with his girlfriend, her 4-year-old son and his 11-year-old son. It's there where police said 4-year-old Gabriel was severely beaten Sunday morning.

"They were serious obviously, and we believe those injuries were what caused his death which prompted the arrest," said Leavenworth police chief Pat Kitchens.

Rivera was brought to St. John's Hospital, the very hospital where the boy's mother works. She was on duty at the time. Jones was at home in charge of watching Rivera and his own 11-year-old son. The older boy is now in state custody.

''We have taken him into protective custody and we're certainly talking with him, trying to figure out what he may nor may not know," said Chief Kitchens.

What police do know is that Jones' story for how Gabriel received his injuries makes no sense.

"We just are convinced that the explanation didn't match the significance of the injuries," said Chief Kitchens.

"It's sad. It's sad it happened right next door," said neighbor Marty Morgan.

Morgan knew Jones as the guy who did deck work for him last spring.

"He did real good work, and I thought he was an outstanding young man at the time," said Morgan. "It's hard to believe. I don't know it's hard to believe."

Jones is expected to be formally charged Tuesday with his first court appearance to follow on Wednesday.

Police said there are a lot of disturbing elements to this case that they're not yet at liberty to discuss, but add their investigation is far from over.