The incident occurred July 10 while the infant's mother was at work.
According to the criminal complaint, 17-year-old Hersen Patrick was watching a 7-month-old and an 18-month-old when the younger child became unresponsive.
The mother returned home to find her 7-month-old son unresponsive and not breathing, prompting her to call 911.
Patrick told investigators the baby was fine "just 30 minutes" before first responders arrived at the scene.
An autopsy revealed the infant had numerous internal injuries consistent with blunt force trauma.
Prosecutors said Patrick told the dispatcher that the baby's heart was beating, but he was not breathing, and the dispatcher instructed him on how to perform CPR until first responders arrived. When the Milwaukee Fire Department got to the scene, the baby's body was limp, and he was "pulseless and not breathing."
The baby was still unresponsive when they arrived at Children's Wisconsin, and court filings said six rounds of epinephrine were needed to regain a pulse. There were "linear abrasions" on the baby's neck, as well as "red, linear indentations under the chin at the top of the neck and above the collar bone."
Two separate brain death examinations took place, and with no blood flow to the brain, the baby was declared dead on July 14. An autopsy found "numerous internal injuries" that were "consistent with blunt force trauma."
Milwaukee babysitter faces charges in 7-month-old death investigation
Authorities seek Hersen Patrick after autopsy reveals infant suffered blunt force trauma while mother was at work
