Cronjob is still running even after deletion

In one of my past project developed in Django python framework, I needed a cronjob to automate some process. I used this django-cron module and installed it as per their documentation. Everything was working as usual. Recently, the project was discontinued and every code and related processes were removed.

But I found that the cronjob related to that project is still running. I double checked with crontab -e, the cronjob is not there. I tried by reloading and restarting the cron daemon, even I restart the whole server, but in vain. If I check in /var/log/syslog, I still can see the cron is running every minute. Here is the output from syslog.

Jul 25 08:33:01 CRON[26412]: (ubuntu) CMD (cd /home/projects/pdf-generator && /home/venv/django/bin/python manage.py runcrons core.myapp.crons.PdfConversionCronJob)

The server is running Ubuntu 18.04.

Does anyone know what is going on and how to remove the cronjob for once and all?

As well as a user's personal crontab (editable/viewable via crontab -e or crontab -l), cron jobs for a user may be run from

• the system-wide crontab file, /etc/crontab

• a file in the /etc/cron.d/ directory

If you are not currently logged in as user ubuntu you can check their personal crontab with sudo crontab -u ubuntu -l or sudo -u ubuntu crontab -l