iPhoto isn't deleting "deleted files" from my Mac

Ok, this is a strange one! I have the latest iPhoto version. 9.4.1. In short, iPhoto isn't physically deleting photos from my hard drive when I delete them from iPhoto.

When I take photos, I like to take a bunch of the same photo. I then import it into iPhoto, select the best ones to keep and then delete the ones I don't want. I then empty the trash, of course. For some strange reason, I felt like digging into the iPhoto Library package file tonight. Don't know why. I guess I was just bored and curious as to what was in there. To my surprise, I found a whole heap of photos, even from months ago, in the Masters folder that I had supposedly deleted. At first I thought it was from my Photo Stream. To make sure, I completely turned Photo Stream off from iPhoto. Turns out it wasn't from Photo Stream. So now I have a whole bunch of photos sitting in my iPhoto Library that A) I don't need and B) iPhoto doesn't even look at. Very strange.

Anyone have any suggestions as to what might be going on? Even in my last import, iPhoto didn't delete any of the deleted photos from my hard drive, and my last import was 3 days ago from 9.4.1. Would love to know what's going on. Thanks for reading and hope to get some information on the matter soon.

Regards,

Daniel