If a Power of Attorney is valid?

If a Power of Attorney is valid? One of the witnesses that signed the POA stated there was no notary present at the time the principal signed this document. But it was somehow notarized later.
This POA was used to obtain $300K plus. Is this POA valid? If no notary was present?
The principal of the POA was an elderly person, age 66, in hospital, disabled from stroke in brainstem.
Wouldnt these actions taken with the use of the POA, fall under Finanical Exploitation of the Elderly, White collar crimes such as Bank Fraud, Embezzelement, Forgery and Larceny?
I hope you can help me. I feel like there are laws broken, but no one will tell me where to go to for help. Or how do I report this?

Power of attorney.

Power of attorney.
What are the duties and powers of power of attorney,with respect to an elderly family member(care responsibilities of that elderly person) and the other children in the family.