An 8-year-old girl is being questioned by police in connection with the death of a 1-year-old boy at a Muskegon, Michigan daycare center.

Police believe an 8-year-old girl who was in the home may be responsible for the child’s death. A 5-year-old child was a witness for what happened to the boy.

The boy’s mother, Bryanna Reasonover, told The Detroit Free Press she left her son, Korey Brown, and 2 other children at Keysha Keepers Daycare when she went to work on Thursday.

She said when she arrived Friday morning, she found the baby unresponsive in a playpen. The baby’s body showed signs of abuse. His mother said he had bite marks on his face and hands.

It’s very frustrating to not know what happened, to know he was suffering when all he probably wanted was his mommy,” she said.

Investigators say 4 children at the daycare were left unattended for a period of time during the night. The 8-year-old girl was one of the children being cared for at the daycare.

According to Fox17 News, workers at the daycare had no idea what happened to the baby.