What is the name of the criminal minds episode where?

I was watching a tivo'd episode and the first few minutes of the next episode was at the end. It is one I have never seen. In it Reid is at a cl or conference where a lecturer is discussing MIRs of serial killers and is discussing the fact that many have MOA? gene and that as fetuses the brains are inundated with serotonin. Then you see a woman in the swimming pool, floating and a man walks into the pool grabbing her. That is all I got. Would love the name of the episode so I can find it and watch it.