wtmpClean is a tool for Unix which clears a given user from the wtmp database.
You can download it from the following link: https://packetstormsecurity.com/files/download/73430/wtmpclean-0.6.4.tar.bz2
Source: https://packetstormsecurity.com/files/73430/wtmpclean-WTMP-Record-Modification-Utility.html