I created a cronjob years ago, now it is still running on the server but I can't locate it with "crontab -e", what can I do?

Question

two years ago I created a cronjob which execute a python script to backup stuff. Now, the thing is that this cronjob is still running:

/var/log/cron.log.1:Oct  9 20:00:02 syslogngsrv CRON[28292]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log.1:Oct 10 20:00:01 syslogngsrv CRON[14596]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log.1:Oct 11 20:00:01 syslogngsrv CRON[936]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log.1:Oct 12 20:00:01 syslogngsrv CRON[19749]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log.1:Oct 13 20:00:01 syslogngsrv CRON[6654]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log.1:Oct 14 20:00:01 syslogngsrv CRON[25544]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log.1:Oct 15 20:00:01 syslogngsrv CRON[11925]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log:Oct 16 20:00:01 syslogngsrv CRON[30679]: (root) CMD (python3 /tftp/autodetect.py)
/var/log/cron.log:Oct 17 20:00:01 syslogngsrv CRON[16946]: (root) CMD (python3 /tftp/autodetect.py)

In syslog logs too:

/var/log/syslog.1:Oct 18 20:00:01 syslogngsrv CRON[3363]: (root) CMD (python3 /tftp/autodetect.py)

ls -lR /etc/cron* output:

root@syslogngsrv:~# ls -lR /etc/cron*
-rw-r--r-- 1 root root 1042 Mar  5  2020 /etc/crontab

/etc/cron.d:
total 0

/etc/cron.daily:
total 28
-rwxr-xr-x 1 root root 1478 May 28  2019 apt-compat
-rwxr-xr-x 1 root root  355 Dec 29  2017 bsdmainutils
-rwxr-xr-x 1 root root 1187 Apr 19  2019 dpkg
-rwxr-xr-x 1 root root  377 Aug 28  2018 logrotate
-rwxr-xr-x 1 root root 1123 Feb 10  2019 man-db
-rwxr-xr-x 1 root root  543 Nov 14  2018 mlocate
-rwxr-xr-x 1 root root  249 Sep 27  2017 passwd

/etc/cron.hourly:
total 0

/etc/cron.monthly:
total 0

/etc/cron.weekly:
total 4
-rwxr-xr-x 1 root root 813 Feb 10  2019 man-db

The issue is that I can't find it anywhere.

crontab -e and crontab -u root -e are empty.

Also

/var/spool/cron/crontabs/

is empty.

I also tried -u flag with other system users but nothing. There aren't other users manually created by me on the server.

Someone can put me in the right way?