BFD (brute force detector) is a cron controlled script that frequently checks log files for signs of brute force attacks -
http://www.rfxnetworks.com/bfd.php
/usr/local/bfd/tmp/attack.pool contains list of IP addresses and services, where the ip addresses are the source of brute force attacks and the services are the services a given ip tried to attack. /usr/local/bfd/tmp/attack.pool.tmp would be a temporary copy of this file.
I imagine that the command 'grep -vf /usr/local/bfd/tmp/attack.pool.tmp ' would be BFD trying to process one if it's data files - nothing more, nothing less.
If this process is taking up a huge amount of resources then it is not running correctly. Perhaps /usr/local/bfd/tmp/attack.pool.tmp was corrupt or contained so many records that it was taking a long time to process.
I'd recommend removing and reinstalling BFD. You might want to contact the makers of BFD to determine how to do this if you've deleted /usr/local/bfd.
In the future, remember not to panic!