Mother 'bashed sobbing toddler's head off side of crib until he was brain dead'

A mother left her 16 year-old son brain-dead after bashing his head off his crib to try and stop him crying, police said.

Chelsea Olinger, 27, was arrested Thursday, three days after bringing her son to hospital and claiming he’d fallen down the stairs.

The youngster was not breathing and did not have a pulse after being taken to the facility in Mankato, Minnesota.

Olinger is later said to have changed her story to claim she ‘may’ have hit her son’s head on the side of his crib, and held her hand over his mouth to try and get him to stop crying.

The incident left the little boy with no brain activity, The Mankato Free Press reported.

He was admitted to hospital with bleeding on the brain, seven fractured ribs, two broken vertebrae and a lacerated liver.

The boy was later transferred to a hospital in Rochester for specialist treatment, and is believed to remain on life support Friday as his family prepares to say their goodbyes.

Olinger has so far been charged with felony assault, but could face upgraded allegations if the toddler dies.

Crime scene technicians were seen working at the apartment complex where Olinger lives in a bid to uncover further evidence about what happened to her son.