In which Criminal Minds episode does Reid discover that the connection between the victims is facial symmetry?

Hello everyone,

I love Criminal Minds, and I remember a scene where the team (I think it was Reid) discovered that the connection between the victims was their facial structure. I seem to remember that all of the victims have one eye slightly lower. I haven't been able to figure out the name of that episode for weeks… does anyone happen to know and can tell me the season and episode?

Thank you very much 🙂