Squatter Has Somehow Put Our House In Her Name.

So my husband's dad left him (and sisters) a house in his will. It is a manufactured home in a manufactured home park. My husband's father was living in it and then he met a woman online and moved to another country and married her. He had been planning on moving back into his home in the US. So he made arrangements with a "friend" of his. He allowed her to live there while he was out of the country. Well he ended up unexpectedly dying before he moved back home. My husband traveled to Arizona (where the house is) from Oregon (where we are) to get everything settled. Well this woman wouldn't leave, so my husband just ended up telling her he didn't want to battle this and told her she could stay there until she passed away (she's in her 80's and not in great health). Well this whole time (over 6 years), my husband has been paying the property taxes on the house (everything, title and all is in his name). But this year when he went to pay the property tax, he noticed the taxes are suddenly in her name. He put in a request to put them back into his name. This prompted us to make sure the house is still in his name, so he contacted ADOT and they told him the house is now in her name. ADOT told my husband to get a hold of the inspector general in Arizona. He called them and they told him to file a report online with any documentation he has.

This is plain and simple fraud, but we have no idea how she was able to do this. We are currently waiting to hear back from the inspector generals office, but is there anything else we should be doing right now? We have been planning to move there when she passed away and or moved out.

EDIT to add:

The owner of the park that the house is in also told us she had scammed a few of her elderly neighbors. I called the park owner today and left her a voicemail telling her what was going on, because she was trying to get her evicted a couple years ago... Dang, now that I'm thinking about that, maybe that's why she is pulling this stunt and maybe thinks she can sell the house before she's booted by the park owner... I'm just still in shock that someone we were helping would do this, so I'm not thinking too clearly.