[Dovecot] ot: tracking messages- luser troubleshooting

[voytek at sbt.net.au]

I had a user complaining of 'not getting emails'
I've searched for sender in maillog, got two messages, both showed up as;

Dec 12 15:51:29 emu postfix/pipe[9607]: 3F21C5E750: to=<xxx>,
relay=dovecot, delay=6.4, delays=6.3/0.01/0/0.12, dsn=2.0.0, status=sent
(delivered via dovecot service)
Dec 12 15:51:29 emu postfix/qmgr[20178]: 3F21C5E750: removed

yes the user claimed the message was not received,

eventually, after traversing through severl directories, I found the
message in '../Maildir/.Deleted Messages'
it turns out it was inadvertenltly deleted on iphone.

there has to be a better way to try to find / resolve such issues ?

what's an optimal way of trying to trace such? I greped for the 3F21C5E750
string through several Maildirs

tia,