“deputies released Razo because he hadn’t committed a crime at that point.”
So sneaking across the border isn’t a crime?
I imagine ICE's thinking is this (don't kill the messenger) --
Sneaking across the border is undoubtedly a criminal offense. However, unlawful presence is not. If police come across an illegal immigrant, they have no proof of the unlawful entry (people can be illegal immigrants but not have committed unlawful entry).