An infant in the Bronx has died after her 5-year-old cousin rolled onto her while they were sleeping.

The New York Daily News reports that the aunt of Ziebella Thorne-Young, who was six months old, found the baby unconscious early Monday morning. The aunt was reportedly babysitting the infant at her sister’s request, and the baby and her cousin were sharing a bed in the home.

Sources told the news outlet that the aunt checked on her daughter and niece multiple times after they went to sleep. But at some point, the 5-year-old girl rolled over onto the baby, accidentally smothering her.

The infant was transported by ambulance to the BronxCare Health System, where she was later pronounced dead.

Authorities have reportedly ordered an autopsy to determine the precise cause of death. It does not appear at this time that any of the infant’s family members will be charged.