Need to search Dovecot mail database for keyword

A Subject Access Request has come to my department and because of this I will need search our email database for a keyword, in this case the SAR requestee's name. We (still) use Dovecot/Postfix on Mac OS Server App to handle our mail. I tried doveadm search command but didn't work. Could someone help me with a simple bash script I can point at my mail database which will go through the entire thing and copy all messages containing matching keyword to destination folder?