my mothers rights to choose whether she leaves her home.

my mother has a power of attorney.my niece.this was done in 2008. in December of 2013 my mother was diagnosed with dementia Alzheimer's type.I came from another state to take care of her.I have 12 years of experience working with older adults with Alzheimer's disease.since I've been here.I have had to deal with a brother that has made numerous calls to adult protective services,with various accusations of abuse.all have been found unfounded.and as a matter of fact the last call he made the APS told him if he called again with false accusations they would have him areested.this brother is my moms power of attorneys father.she has never done one thing to help me when I have begged her to stop her father from causing the stress and interruptions in my caring for.my mother.she was tested again this June of 2015. those results stated she had moderate stage Alzheimer's disease...heres my problem.after all this time since my mom was diagnosed.and absolutely no help fro. my mothers power of attorney.she has never even paid a bill.I set up auto pay forher bills along time ago.she owns her home and has quite a little nest egg and income.she could actually afford 24 hour home health care.at least for another couple of years..now as I said.I quit asking for my moms power of attorney for help along time ago.I have had to put up with a lot from my two brothers that have nothing to do with my mothers care.it has taken a toll on me..now about three weeks ago I out of the blue get a text message from my moms power of attorney my niece that says .I have decided to become grandmas decision maker ,so that means I will be there Sunday night and leave with grandma to bring her to live with me on Monday.this was on Friday.I was shocked.and I'm still in shock.when she came, we had to call the police because my mother had told her no in no uncertain terms.she kept badgering her.the police told power of attorney.my niece that if she did not want to go she could not force her.the police asked them to leave.two days later,while I was not home.my niece,power of attorney came and told my mom she had a doctor's appt.she told my brother who was here,that she just wanted to check with doctor before she goes home to make sure my mom was fine...so my brother encouraged my mom to go.we have not seen her sense. now my question is,is it a crime to have tricked my mother after she had absolutely refused to go.and in front of numerous family members and four police officers not two days before.my mother has never been in another ho.e for more than 46 years.she was very clear as to understanding what was going on.she said no.I have read to do this exact thing is abduction and that I should call the police ..is this true.and should I report it.I believe I should.but I don't want to if it is not a crime .I don't know what to do.please help.