The best dog any owner could've asked for died saturday night in her sleep. I woke up to her laying down in the same position she sleeps in went to the bathroom then came back and called her but she did not move. She was stiff as a board and rigor mortis had set in. I tried pounding on her chest but it was no use she was already gone. She would've been 6 yrs old September 1st. We did a necropsy and the vet could not find any clear causes of death. She looked at all the major organs, lungs heart, kidneys, stomach, spleen and could not find anything. The only thing that happened was a week prior she got into an altercation with a male pitbull (who had a muzzle on) and the pit bull still was able to bite my dog. I checked her after the altercation and could not find any blood/ wounds. 2 days pass and I grab her collar and she yelped. So I looked under her collar and there was a silver dollar size red wound with a bite mark the size of a tooth that really wasn't that deep but was infected. I brought her to the vet and they sedated her, drained the wound, and gave her antibiotics, a pain killer, and a antihistamine for the itch. I felt guilty that I did not catch the wound earlier but the vets reassured me that it was ok and she would be fine. A WEEK LATER she dies in her sleep. The vet said that it could've been a blood clot that formed under the skin that we could not see that might of dislodged and traveled to her brain or any other major organ but she said that would be very rare. The other theory is she had something wrong with her heart, like a cardiomyopathy or something like that. My first inclination says it has to be something with the bite, but the vet said she has seen dogs with 20 bite wounds come in, all deeper wounds than my dogs one tooth mark and all of those dogs were fine and did not die. the necropsy was $100 but to send off tissue and blood it would've been and additional $400-500, so we just did the necropsy. Has anyone heard of blood clots from small bite wounds causing a dog to die in its sleep? Or anything on cardiamyopathy where her heart could of swollen but only detected by a ultrasound and just looking at the heart through a necropsy would not of shown anything? I'm just trying to find out what happened and having a hard time accepting that I will never know. It was so sudden. The only other thing I noticed was how clingy she was to me lately, she always had to be around me and would sometimes sit and stare at me. Usually in the past that was just to let her outside, but she would stare at me while I would be on the couch and I would walk to the door and she would not want to go outside. We moved to a knew state where my wife is from and Idk if she just missed her old home. It was not like she wanted attention from me though, it like she was telling me something. I'm not sure if she was telling me that she was sick or that something was wrong.. Idk, maybe it was that she just needed attention. She acted fine and was active and loved to be outside. I don't know if I'm reading into it too much. She was the most loving dog in the world. If anyone has any experience with any of this please let me know. Anything helps right now.