Was this customer a prospect?

Hi,

Is there a way to determine if customer 123 was previously a prospect?  I'm looking at the database and when you convert a prospect to a customer the prospect record is deleted from smmBusRelTable.  I'd like to automate some reports for our sales guys (external to AX) to give them a list of prospects that have been converted to customers for the week.

Thank you for your help.

Cheers,

Bob