Your bonsai may have been a ficus, but I'm not sure of that. Someone with more expertise may come by to confirm that.
You can tell if it is still alive by scratching the bark [scraping a bit of bark off] and see if it is moist and green underneath the bark. If so, the tree is still alive. If dry and brown, it is dead.
It looks like you have your bonsai in a work environment, which rarely works out. It needs a lot more light than it would have been getting. Either it should have been sitting right in front of a good south facing window or it should have had its own lamp shining directly on it from just a few inches away.
The soil it is in looks very dense and moisture holding. Soil for bonsai trees should be very loose and free draining, mostly mineral and gritty.
Check out the articles on bonsai care here: https://www.helpfulgardener.com/bonsai/
If it is dead, do some reading and learning about bonsai before you replace it. If it is a ficus, it is possible it is still alive. Ficus are famous for easily dropping all their leaves when they are moved, or conditions aren't right for them. Since they easily drop their leaves, they also easily replace them.
Let us know what you find and how it works out for you!
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