Did the little girl tell the cops and FBI that Hoffman was the killer?

That's never brought back up again and the scene was only included on the director's cut of Saw VI. Both Perez and Erickson seem suspicious of Hoffman throughout VI, so maybe she told the police after being rescued which is why they were suspicious to begin with. Then again, you could assume they were suspicious of Hoffman because they were already re-investigating the pendulum murder.

In VII it comes as a complete surprise to Gibson when Jill reveals Hoffman's involvement in the Jigsaw legacy, so if the girl ever said anything at all the information probably only reached Erickson and Perez.