Mapped drives to same server

One of our developers ran a program on a server that mapped about 15 drives to one of the servers local drives. These mappings cannot be disconnected nor can they be deleted with net use /delete. In fact they do not show up as mapped under net use, although they show up in My Computer and can be used to access the drive. When we logged out and back in, we got the messages saying “cannot reconnect, drive already in use..” And the drives were still there.
Any clues as to how I can get rid of these?