Copilot for searching mailbox

Hi Folks,

I have a law firm client who wish to search for all relevant emails and attachments relating to a particular matter.  Has anyone developed a solution using Copilot?  In the past there was a commercial product called Aftermail which mirrors the mailbox with its own database that included title, email content, attachment, cced/bcc users etc.  For example, you could search for all attached files or emails that contains a specific key word.  

Thank you in advance.