CINCINNATI - Allegations that workers at a church day care put an over-the-counter dietary supplement in candy to help children sleep at nap time are under investigation, police said yesterday, and the church's pastor said two workers have been fired.

Springfield Township police Lt. Dave Schaefer confirmed that police are looking into allegations that some workers at Covenant Apostolic Church Daycare in suburban Cincinnati gave melatonin to some children there. He did not give the ages of the children.

Police have sent a letter to parents and guardians of children who attend the day care, informing them of the investigation.

Dated Monday, the letter said that the investigation had just begun and that police did not know which staff members allegedly gave the supplement to children or how many of the 40 or so children who attend the day care allegedly received the supplement.

Melatonin is a hormone made by a small gland in the brain. It helps control sleep and wake cycles and is not FDA-approved or regulated, according to the Mayo Clinic Web site. Possible side effects include dizziness, abdominal discomfort, headaches, confusion, sleepwalking and nightmares.

The site also says that long-term effects of melatonin are not known and it may not be safe for anyone who is pregnant, breast-feeding or younger than age 20.

Laura Satterfield told WCPO-TV that police said employees acknowledged having given her 9-month-old grandson melatonin in his formula to help him sleep better. She said he was at the center only one day a week but has had trouble sleeping on visits to her home, including once being awake from 4 a.m. to 5 p.m.

"He would not sleep," she told the station. "He would sleep for about five minutes and then he's up."

She said she wants the workers punished.

"I want these women to be humiliated. I want people to look at these women and say, 'You gave drugs to kids.' "

Pastor Shelly Hendricks said he discovered on Sunday that some children had been given melatonin by staff members, but he declined to explain how he found out. Since then, two staff members have been fired, he said.