2 administrators left the company and their user's ID were deleted. But I found that they left the crontab files under /var/spool/cron/crontabs. Moreover, I believe that when they were in the company, they modified their profile as root(I mean, they modified the /etc/passwd file and change their user ID number to 0).
Now I doubt if their crontab files are running, and can I use the command "crontab -r username" to remove their crontab file, or just delete their crontab files that under /var/spool/cron/crontabs directly.
If you think this question should be value more points, please let me know. Thanks a lot!