How would I find out if a caregiver has been ever reported for elderly abuse?

Not sure if this will you but I found a website called, "National Center on Elder Abuse." It offers states elder abuse reports.

http://www.ncea.aoa.gov/ncearoot/Main_Site/index.aspx

Every State has under Social Services a Department for Protective Services for both children and elderly, so you should investigate and they can steer you in the right direction because if there has ever been a report filed whether the report was proven to be false or true. I hope this helps.

Do your own criminal background check --- which brings us to the question: what site does everyone use for the criminal background check? I have used publicdata in the past. The problem with the criminal background check is that there isn't one that is totally comprehensive so if you want to be thorough, you need to think about a state check through DPS and then, a local one through the sheriff's dept.

Ask the caregiver for a police report.

If you've hired this caregiver through an agency, they should have done a thorough background check. If she ever was reported for elderly abuse, the agency never should have presented her to you in the first place. If nothing is on file, go to the police station and ask for a police check.