I think my mom's healthcare aide is drugging her with tylenol pm. What should I do?

I saw her on a nanny cam once giving something to my mother and saying this will make you sleep very well tonight. I couldn't figure out what it was. Then, the other day, the weekend aide told me that she herself had trouble sleeping one night and the aide I suspect gave her tylenol pm. When I researched it, it fit together. It is made up of acetaminaphine and benadryl. Apparently not detectable in a 10 panel drug screen. I don't know what to do.