I think the question pretty much says it all.

The suspicion of child abuse is based on the child's behavior with
other children. The children are all enrolled in a daycare facility
that also has pre-school education acredidation.

Yes! Teachers and child care workers are required by law to do so.
Laws vary from state to state, but all 50 states have child abuse and
neglect reporting laws. Not reporting suspected abuse can result in
criminal charges against the teacher or caregiver. Some states have
laws requiring *anyone* suspecting child abuse to report it.
 
Here are some relevant articles:

Good overall article:
http://www.cwla.org/articles/cv0111teachers.htm

Some legal aspects:
http://www.smith-lawfirm.com/mandatory_reporting.htm

A list of phone numbers for reporting:
http://www.acf.dhhs.gov/programs/cb/publications/rpt_abu.htm

State Statutes:
http://www.calib.com/nccanch/statutes/statutes/tblDefine_search.cfm

U.S Department of Health Prevention Initiative:
http://www.calib.com/nccanch/prevention/index.cfm

Hope this helped. If you need further information please ask for an
answer clarification before you rate this answer. Thank you!

-shiva777

search strategy:
law childcare "report abuse"
law teacher "report abuse"