A Wisconsin babysitter smiled in her mugshot, after being accused of murdering a two-month-old male infant that she cared for.

According to police, the infant's mom picked up the baby at the babysitter's house, and put him in his car seat. When the mom went to get her son out of the car seat, she found him unresponsive.

The infant's mother had just returned to the laundromat after picking up- the baby at the babysitter's house, located on the 3600 block of North 6th Street. When the mom went to get her son out of the car seat, she found him unresponsive.

The baby was pronounced dead on scene, and preliminary information led investigators to believe he was killed while in the care of the babysitter.

The mom immediately called for an ambulance, but it was too late. Investigators were led  to believe he was killed while in the care of the babysitter.

The babysitter is 28-year-old Marissa M. Tietsort. She was arrested and charged with child abuse. She was arrested pursuant to the warrant, and will appear in Marathon County Court on Monday, to face charges different than this incident.

On Friday, an autopsy was performed on the infant boy in Madison. Based on initial results, his death is being investigated as a homicide.

Charges against Tietsort are expected upon completion of this investigation and review of final autopsy results.