On Zev Brenner's Talkline radio show tonight, Rabbi Paysach Krohn spoke out against child sex abue, but when asked about reporting child sex abuse to police, Krohn said that unless you are 100% sure the abuse took place (which essentially means you have to witness it happening), you should ask a rabbi for permission to call police.
Krohn is an Artscroll author and a Agudath Israel of America member.
He is also a brother-in-law of Rabbi Ephraim Bryks, who is an accused child sex abuser.
Krohn is also on the board of Ruchie Frier's Baderech organization that tries to keep "at risk" haredi youth from becoming secular. Frier has said that many of her "at risk" kids were sexually abused.
Here's the audio. Please click the gray bar to listen: