When someone is not in the sudoers group and try to use sudo, get an error message like this one:
yzT is not in the sudoers file. This incident will be reported.
I'm trying to figure out in which log this information is logged, for check who tried to run a command with sudo for example, but can't find it.
The first Google search says
/var/log/syslog but I don't see any information related to sudo there.