Quick Exchange Server 5.5 question.

[Rogue]

We fired a guy a few weeks ago but he had set e-mail for deferred delivery. Well, his e-mails still keep coming, despite the fact that we deleted his mailbox. Is there any way to get rid of the five e-mails awaiting delivery in the future? I used the Performance monitor to determine that there are exactly 5 e-mails left to be delivered. So, how do I get rid of them, taking into consideration that his mailbox is already deleted?