(AP) — Authorities say a 4-year-old boy who was left behind at a Fremont park by day care workers has been returned to his mother.

Fremont Police Lt. Kurt Bottorff says officers found the boy in Memorial Park on Tuesday after someone called to report a possible case of child neglect.

Officers were told by a bystander that the boy had been at the park without supervision for 30 to 45 minutes after the group from the Sparkle Haven Child Care Center left.

A representative for Sparkle Haven didn’t immediately return a call Wednesday from The Associated Press.

Bottorff says the Nebraska Department of Health and Human Services will be investigating.