Whether it was with the Jets or some other team, Crabtree's stance made no sense without some sort of guarantee from another team.
When the investigators actually began poking around, teams are like... "wait, if we redraft or trade for the kid and give him $40 mil, what is that gonna look like?"
Or it was the jets and they had Braylon Edwards in the works.
The Niners probably won't get shit for the tampering, but calling for the investigation probably helped getting Crabtree to the table.