Found: YA girl mystery

The book is nonfiction. I read it last year I think so that it isn't very old.
The main character is about 16/17 year old girl whose mother died( i think) and she is sent to live with her great aunt. i know that there was a party in the house thrown by her grteat aunt the first night. i also know that somewhere later in the book ther is another party at the house and someone dies by falling off the roof.

i also think there is some kind of tale or story that her grandfater his some kind of treasure in the house or near it and people want to try and find it.

she also goes to a county club where she meets one of her friends fathers who later turns out to be after the treasure aswell. but when she meets him he says that he thinks it is not real.

then she tries to find it herself, but i don't remember if she is successful.

and then her great aunt is dying and a home nurse somes to take care of her.

thank you in advance for everyone, who comment and help me get closer to finding the book. all the help would be greatly appreciated.

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I found the book, it was the first in the series "Pawns of patience"