Arthur Aronov If you're aware of the program that's the culprit for sending the multiple emails, I'd dig into that program using either smart lists or email performance reports. The email performance report will show you exactly when an email is sent (first/last activity) whereas a smart list (with say a "was sent email" filter with a date constraint) will show you who actually received the specific emails on a set date.
This being said, is the program sending the same email setup as an Engagement Program or just a standard default program sending emails from a smart campaign? If the latter, there could be a recurring schedule (or wait steps) that are causing the same email to send over and over.
Hope that helps to get you started!