According to the Pinellas County Sheriff's Office, 30-year-old Burgandie Marquez told detectives she became enraged during a phone call with the baby's father on Thursday, and intentionally and forcefully jerked the child up from the ground twice, causing the infant's head to snap backward.
Marquez said she then placed her baby underneath her arm and ran up and down the stairs inside her Palm Harbor home, allowing the infant's head to bounce up and down without support.
Detectives said she admitted that she knew she had been too "rough" with the baby.
The next morning, Marquez noticed the 5-month-old was having seizures, but tried consoling the baby instead of taking him to the hospital.
That afternoon, Marquez decided to take the infant to Pasco County to meet the child's father, but stopped at a gas station when the baby's condition worsened and said she needed medical attention for his seizures.
Paramedics airlifted the baby to St. Joseph's Hospital for life-threatening injuries. Medical staff at the hospital told detectives the child suffered a severe brain bleed caused by head trauma. He remains in critical condition.