Frieza in “Unfinished Business”

[about Gohan] Strange. Where did the little one get all his power? That kid's stronger than any Saiyan I've ever fought. Hmm...I better keep my eye on that one. I wonder who he is. I'm sure I eliminated all the Saiyans except for Vegeta, Nappa, and Raditz twenty years ago. How'd he survive? Neither one of those misfits could possibly be his father. No matter. In the end, they all must be exponged anyway.