The reason this childcare worker was arrested will shock you to the core

A childcare worker has confessed to spiking the sippy cups of 10 toddlers in her care. 

Debbie Gratz, 59, allegedly broke up sleeping pills before slipping the pieces into the children's drinks. Police investigators do not currently know how many pills were used.

According to ABC News, California's Morgan Hill School terminated Gratz for "failure to follow Kiddie Academy standards and processes.”

A fellow employee noticed Gratz placing an unknown substance in the cups and informed school officials. When they confronted Gratz, she admitted to adding sleeping pills to the sippy cups.

However, because police were not notified until a few days later, much of the evidence for the case has been lost. This includes the spiked sippy cups, which were washed out and rinsed.

Gratz was arrested following a search warrant at her house, and was charged with two counts of child endangerment. She will appear in court later this month.

Disturbingly, parents of students at the school were offered no explanation as to why Gratz had been fired.

The mother of a two-year-old who had been in her care prior to the event said the truth only emerged when the case appeared in the US media.

“Sickening, sick to my stomach, I want to throw up,” she told TV station KGO. “I’m not angry, I’m just sad. Disturbing. I don’t know what to think.”