Identify mail for attachment hash

[Daniel Miller]

How can I find the message associated with a given attachment hash? For 
example, if I know that:

/ff/23/ff23873c712474ad0f48cbd81485eaeaba3d8468-e1b4513a2eb8eb53b16400009db5accb

is missing, I want to find the message associated with it so I can 
determine if it's critical and I need to recover it from another source, 
or if I can simply delete the old message.

-- 
Daniel