I seem to have fallen victim to a similar scenario. My girlfriend bought me a Bonsai and the same thing happened. After identifying and researching the species I wondered if it was dormant or simply dead. Whoever is at fault, I'm leaning towards dead, even though I'm pretty sure I never over or under watered it. I'm getting ready to dump it out and analyze what sort of soil is in it / what the roots look like. The top of the soil had been covered with a glued-together rock covering with broken rocks for a visual appeal, who knows what's actually underneath it. At least I have a pot for future Bonsai endeavors and it got me into the hobby.

Diplo: For next time: Remove such layer of rocks., That is actually what caused the death of your tr5ee. The soil can't accept the water and/or has a hard time to breathe.

Leatherback you are probably right. I did chip away at the top layer of rock but probably not before it had already died. Also, foolishly, I had been keeping it indoors out of fear that it would freeze. This probably didn't help because it should be an outdoor tree from what I understand. Anyway, valuable learning experience was had!