Tree Identification

Hi all! My boss has a bonsai tree that is severly neglected. I thought it was dead, but it's showing subtle signs of life (it sprouted a few sad leaves recently). It may be beyond repair, but I want to at least try to revive the poor thing. Does anyone know what kind of tree this is?

This image is hidden for guests.
Please log in or register to see it.

This image is hidden for guests.
Please log in or register to see it.

     

This plant is dead, it may have a few bits of leaf, but it is dead. Firstly it is inside, that was the killer. It looks extremely dry, that made it even worse. At a guess it could have been a Japanese Quince or possibly Hawthorn as it has thorns so it could be either but there is no hope for it I am afraid. If this was mine I would put it outside in the shade and water when I did all my other plants and wait but I would not put money on it living.

It's not a Hawtorn, it has compound leaves, like a robinia ( but this is not robinia )
Maybe some sort of  acacia 

My first hunch was acacia. But really impossible to tell for sure based on the photos.

either way it is not alive as in dead.

Hello,
That's a Brazilian Rain Tree, or maybe it was...
I can see the branches still green, it means it is alive for that species, I don't know if it still has the energy to bud back, and you said it already sprouted back once, so that's not good news...
It's a very sturdy species, so it could bud back, maybe if well placed in half shade outside, I've seen they come back from worse than that, but it depends a lot on how the tree was being treated before...

Unfortunatelly, I might be late.