Administrator Completes on Mortgage

[Tracker24]

So my father died intestate January 2022, and my mother became administrator of the estate, there were four beneficiary's - my mother, myself and two other brothers..

I have just found out without the knowledge of two beneficiary's (myself and one other brother), the administrator and one son directly after my fathers death took out a mortgage against the estate?

Now the mortgage was sizable £100K +

I obviously confronted my mother (the administrator) who denied all knowledge and accused me of trying to sabotage the process of administration for my own gains and now refuses to speak with me?

So.. I have do some digging and now very concerned with what I have uncovered, and now looking for some advise on the best way forward?

It turns out my father had made the mortgage application to buy land/property before his untimely death, my mother then made the decision not to inform the bank of his death and let the application go through and the money was paid out...

That in its self is bad enough, however after a bit more digging I have found out the following:

• The money was indeed used for the purchase of land and property, land registry shows the registered owners as my mother and one other son, and the purchase price in February 2022 was exactly to the penny the same amount as the mortgage?
• Bank record show that the money was paid into the joint bank account of my deceased father and my mother?
• Bank records also show the application was completed used my fathers personal bank account?
• More concerning Bank records show a standing order has been set up to make monthly payments from the joint bank account into my fathers personal bank account reference (S/O Mortgage) to meet the mortgage repayments?

To me this whole thing is fraud? again I have confronted my mother (the administrator) to give her chance to explain, her response..

"It's nothing to do with you! you don't know what your talking about, and I am not talking to you!"

What do I do?