actually, there is evidence saying it died,and i dont usually think the grim-dark crap, in red blue, before you go to lavender town you fight blue's raticate, then when you go to lavender town and fight blue he asks what you're doing here because you dont have any dead pokemon, this is also the first battle raticate is not on his team, plus red blue was a little darker then the rest of the games. and there is nothing to prove against the fact that you might have killed it. it's still a theory, but there is no false evidence in it.