Benjamin Kingan parents had trusted the staff at the Minee Subee Day Care Center, but Wednesday afternoon, police say a teacher's assistant, 22-year-old Melissa Calusinski, became so frustrated she threw him to the ground.
"She told investigators she was having issues with children in the room. The children were making noise and things like that. She just lost her temper and threw the child down," said Adam Hyde of the Lincolnshire Police Department.
Police say 16-month-old Benjamin of Deerfield, at first, showed no outward signs of injury. He crawled across the room, picking up a blanket and toy along the way, before climbing into a bouncy chair and eventually losing consciousness.
"The injuries are not immediately fatal. The injury to the head causes swelling and damage to the brain which takes time to cause the child to become unresponsive," said Lake County Coroner Dr. Richard Keller.
A total of eight children were in the room at the time the incident happened, along with two adults. The other day care staff member told police she did not see the incident.
Calucinski is the one first noticed Benjamin wasn't breathing and summoned help.
An autopsy revealed the child suffered a fractured skull and bleeding near the brain.
"A child falling ever from the height of a shoulder in and of itself would not do this sort of damage to the brain or cause the skull to fracture. It takes basically a much higher fall or an adult exerting pressure on the child as they are thrown to the floor," Keller said.
Calusinski is being held in the Lake County Jail on $5 million bond.