Which mailbox is causing database content indexing to fail?

Exchange 2010 SP2

Content indexing on one database causes memory and CPU to max out on all DAG members. I have isolated the problem to a particular database.

1. I stopped the search indexing service
2. Created a new db and moved all of the mailboxes from the bad db to the new db. 
3. I then deleted the old DB along with its files.
4. I turned off indexing on all databases and removed the old catalog files.
5. I restarted the indexing service.
6. I re-enabled indexing on one database at a time, waiting for each one to complete before starting the next one, saving the new db for last.
7. About 1.5 hrs into indexing the new db, the memory usage and cpu maxed out on all dag members, essentially crashing the whole system.

Since the problem followed the mailboxes to the new db, I believe the problem must be with one or more of the mailboxes. There are no event log entries that appear relevant. Just messages about quota limits on archives and mailboxes, etc. Nothing that would indicate a problem indexing anything. 

How do I find the problem mailbox?