Cron job still runs despite being deactivated and then deleted

I am receiving email alerts that should be coming from a cron job I set up.

I deactivated the cronjob this morning but am still receiving emails from the script.

A less on /etc/crontab showed the cronjobs had been removed.

I've just deleted the jobs under task and it continued to send me alerts for about 5 minutes, although nothing since so perhaps that's done the job.