A Wisconsin babysitter allegedly killed a 2-month-old baby and then pretended he was still alive when returning him to his mother.

Marissa Tietsort of Wausau was charged Friday with first-degree intentional homicide in the death of Benson Xiong, who was identified in a family Facebook page.

Authorities said Tietsort, 28, killed Benson, dressed him in his snowsuit, placed his body in a car seat, and covered him with blankets. She also allegedly told authorities she pulled a hat over the infant’s eyes so his mother would think he was asleep. It wasn’t until later when the mother removed him from the car seat that she realized he was not breathing and was cold to the touch. She immediately began CPR while her sister called 911 for help, according to the criminal complaint.

Authorities who responded to the scene found Benson with an ashen skin tone, a clenched jaw, and blue lips. He was pronounced dead at the scene.

An autopsy determined that the infant died of significant blunt-force head injuries with multiple impacts to his head. His tailbone was also broken off and displaced, indicating that a significant amount of force was used.

The mother told authorities she had dropped Benson and his older brother off at Tietsort’s house on Oct. 18. Later that day, Tietsort texted the mother about a news report that she had been charged with child abuse and was not to be in contact with children. Tietsort told the mother not to tell anyone that she was watching her children, the criminal complaint stated.