SENECA FALLS, N.Y. -- A 3-year-old boy is on life-support in a Syracuse hospital after being seriously injured by his parents in Seneca Falls, police said.

Donald P. Bovio and Alison C. Bovio, both 38, of 25 Peterman Road, were arrested Monday by the Seneca Falls Police Department and charged with assaulting the boy, police said.

The boy is Alison Bovio's son and Donald Bovio's stepson, said Seneca Falls Police Chief Stuart Peenstra Tuesday during a news conference.

The assault happened three days ago, police said.

Donald Bovio called 911 at about 11:40 p.m. Saturday and told dispatchers his stepson had fallen down the stairs, Peenstra said. When police arrived, the boy was unresponsive, he said.

"It's a horrific scene that we had to process," the chief said. "It's difficult to see this type of injury to a child. That's why we do everything we can to make sure justice is brought."

Donald P. Bovio beat the boy with a belt, according to a felony complaint filed in Seneca Falls Town Court. The child's head hit the floor and he became unconscious, court records said.

Because of the assault, the child can't breath on his own and has bleeding on his brain, court records said.

The boy was airlifted to Upstate University Hospital with "substantial" trauma to his head and body, Peenstra said. Medical personnel told police the boy's injuries did not match with a fall, he said.

Investigators charged the couple with first-degree assault, a felony. The charges carries a possible 25-year prison sentence.

"This is the worst case of child abuse I have ever seen in my career. By far," Peenstra said.

Police said more charges are pending in the case.

The boy remains in critical condition on life-support at Upstate, Peenstra said.

The family moved to Seneca Falls from Salem, Massachusetts two months ago, Peenstra said. Police were called to the home once for a well-being check, he said.

The couple are being in the Seneca County Jail in lieu of $50,000 cash or a $100,000 bond.