better spam features to zap an offending user along with all their comments

we've been hit by spam recently; someone registers and then posts spam to our JIRA. We'd like an easy way to

find the spammer based on a user name (rather than email) as we've zillions of users and can't find their user account to delete it.

(ii) a way to delete all comments from that user with one click.

To see the spam, click here...

http://www.google.com/search?client=safari&rls=en-gb&q=massagelondon+site:logicblaze.com&ie=UTF-8&oe=UTF-8

e.g. http://jira.logicblaze.com/jira/browse/AMQ-169?page=all&decorator=printable

The user appears as 'massagelondon' but the user name is not clickable for some reason (whereas all others is)