By Mark Gomez

MORGAN HILL -- A day care worker in Morgan Hill suspected of putting sleeping pills into children's drinks has been arrested on suspicion of child endangerment, according to police.

Deborah Gratz, 59, of Hollister, was fired Friday from the Kiddie Academy Childcare Facility on Monterey Road after a witness saw her put a substance into the cups of several children, Morgan Hill police said. Facility administrators confronted Gratz, who admitted that she placed an over-the-counter sleep medication into the cups.

Police say none of the children drank from the cups on the day of the reported incident, according to Sgt. Troy Hoefling. "We are still investigating to try and determine if this has been going on for some time," he said.

On Monday police began an investigation into allegations Gratz had slipped Sominex into the cups. Police believe the incident happened before a scheduled nap time.

She was arrested at her home later Monday.

Police say Gratz's motivation is still under investigation.

Gratz has been a teacher at the Kiddie Academy for the past five years, according to police. Her primary responsibility was a class of toddlers ages 1 and 2, and she was responsible for about 10 children.

Anyone who may have information regarding this incident or anyone who believes that their child was under the care of Gratz while at the Kiddie Academy should contact Morgan Hill police detective Joe Burdick at 408-779-2101 or the anonymous tip line at 408-947-STOP (7867).

Contact Mark Gomez at 408-920-5869. Follow him on Twitter @MarkMgomez.