Can a person with a criminal background be a POA?

Amielinj, can you just clarify - your sister has a criminal record for fraud? Your brother has been charged with but not convicted of violent behaviour (not convicted means not guilty, by the way)? And it's your brother whom you know to have been misusing your mother's money?

But has either of them actually been given documented, signed, formal Power of Attorney by your mother?

You go to court and have a Guardian appointed. The Judge will decide who is best for the job and does a complete background check. Often they appoint an independent third party, usually an attorney.

Your mother can assign whomever she wants to be POA, it doesn't even need to be a family member. Sounds like someone will need to hire an Accountant and have that person be assigned as the financial POA.

I don't know what to do anymore. My oldest brother is taking care of my moms money and hes been using it for his personal use. Ive contacted adult protective service but they seem to not do anything about it

And my oldest brother has a violent behavior charged background. Bad temper

Then I would make sure your sister isn't appointed POA.

I can appoint whomever I want as POA as long as their 18 or older. But I sure wouldn't appoint someone who has a history of theft and forging. That's just begging for trouble.

My sister has a long history of theft background forging

Yeah, that's what that means. If the criminal background includes grand larceny, embezzlement, theft or any other financial crime, there'd be no wisdom is appointing them, but they could certainly serve.

so anybody with a criminal background can be a POA

Yes.