Socket.io Different Client IDs

I'm trying to make a simple multiplayer game using websockets and socket.io.

We've got most features working, and our problem now is finding out who the winning player is.

So the solution we're trying to implement right now is by getting sockets on run time, and when a player dies, they send a message to the server. The server on receiving this message adds a property 'dead' to the socket. So socket.dead = true is set when the player dies.

We then check a list of connected sockets (obtained dynamically) to see if there is only one remaining player alive (by checking if socket.dead is defined). One thing we realised is that the socket.ids of connected sockets actually change - and this is prooving to be a problem for us...

The question is where and when does the socket ids change, and how can we detect these changes so that we update our game data?

Thanks