I also think it could be the bolivian. I have a male in my 55g and he is pretty fiesty. I haven't actually seen him take a chuck out of the other fish's tails, but my dominant angel had a chunk missing from her, so I suspect the bolivian. My dominant angel doesn't take any crap from the other angel, so I don't think it was him.
If not the bolivian, then it could be the tetras, but usually their nips aren't that severe.
Watch the bolivian closely for awhile and see if she is misbehaving.
Sorry about your loss.