Detective Tara Augustin

And

I still cannot... I just still can't wrap my head around that.

I think that Eugene thought no one was home and didn't expect for Leslie to be there.

And she came downstairs and confronted him.

And I think in his mind, he realized he was caught because it's not just a stranger.

It's somebody who knows exactly who he is.

And instead of just admitting that he was wrong or talking to her about it, I think that he just panicked and only thought about himself and made a selfish decision to kill Leslie in the heat of the moment just so he could get away.