The Precious Gifts Care Center in Dunellen is closed after a tipster told a family their child was being given melatonin.
"I can tell you that emotionally this is a lot for him, a lot for his family. He is very vulnerable for his age and also because he is on the autism spectrum," Crystal Pettiford, attorney for the family, said.
The owner, 57-year-old Cheryl Ambicki, was detained by police.
Ambicki said she would not speak about the case, under the advisement of her attorney.
The family that reported the incident chose to remain anonymous for the security of the child, but they are livid.
"The trust was severely broken where my client had to learn this and thank god for the tipster for this extreme negligence," Pettiford said.
Inspectors from the state Department of Children and Families paid a visit to the daycare facility.
Its report says not one, but two children were given melatonin without their parents' permission.
It also outlined a list of changes for the facility to make.
The Middlesex County Prosecutor's Office is investigating.