The dog died....

The dog we had been "trying out" went back to her pack last week. She was peeing everywhere still, and was dog agressive and people shy. We had her at our house for almost 3 months and things were still pretty bad on the submissive peeing thing. If you went to pet her, she peed. Even if she'd just been out, she would cower down and pee. She was an okay dog, kind of whiney, and too timid for me to be comfortable with her. Overly submissive dogs are the ones that will turn on you. But anyway, we ended up taking her back to the friends we got her from. She just wasn't working out. I got a call on Tuesday that she was sick, and an email which I got today telling me she had died. She was eating some, and drinking well, but very quiet and she was bleeding. I'm still not sure which end she was bleeding out of, but evidently there was a lot of blood.
I really think she was all right when we took her back. The only thing out of the ordinary with her was a month or so ago, she ate some charcoal and that made her have some bloody poo. It was fine within a couple of days, and we were very careful after that, because she would dump the grill over to get it. But she seemed fine. Ate and drank and peed and pooped normally. I don't know what she got into that hurt her, or if she had something wrong with her from the start that didn't show up until now. I don't guess it really matters. She's just as dead either way. But I'm sorry she is gone. She was a very loving pup, and a good guard dog.