Joshua Casteel, a former U.S. military interrogator at Abu Ghraib, is asking John McCain to renounce his recent position on torture.

McCain once sponsored legislation to ban U.S. military personnel from using torture as an interrogation tactic. But this year, McCain changed his position and voted against an anti-torture amendment to the intelligence authorization bill.

In this video, Casteel says, “When I served in Iraq, every camera in the world was pointed at Abu Ghraib and two things happened as a result. Practices at Abu Ghraib vastly improved, but the dark activity which previously happened there went elsewhere. Techniques [in other prison facilities] included induced hypothermia, smashing hands with hammers and all sorts of activities which clearly are within the bounds of torture by any reasonable, humane standard.”

Casteel is speaking out, along with Father Roy Bourgeois, founder of School of Americas Watch, encourage people to sign on to a petition urging Senator McCain to renounce torture. So far, 20,000 people have added their names. The petition drive is sponsored by Catholics United, School of the Americas Watch, and TrueMajority.org. Click here to sign on.