A settlement in a landmark lawsuit against two psychologists who helped design the CIA's harsh interrogation methods used in the war on terror marked the first time the agency or its private contractors have been held accountable for the program, legal experts said. The deal in the lawsuit from the American Civil Liberties Union also makes it unlikely the CIA will again pursue the tactics, said Deborah Pearlstein, professor at the Cardozo Law School in New York. This sends a signal to those who might consider doing this in the future," Pearlstein said, adding, "This puts an exclamation mark at the end of 'don't torture.'" Terms of the settlement were not disclosed, but it avoided a civil trial set for Sept. 5 in federal court. The ACLU sued psychologists James Mitchell and John "Bruce" Jessen on behalf of three former detainees, including one who died in custody, who contended they were tortured at secret CIA prisons overseas. Mitchell and Jessen were under contract with the federal government following the Sept. 11 terror attacks. The lawsuit claimed they designed, implemented and personally administered an experimental torture program. The techniques they developed included waterboarding, slamming the three men into walls, stuffing them inside coffin-like boxes, exposing them to extreme temperatures, starving them and keeping them awake for days, the ACLU said. A U.S. Senate investigation in 2014 found that Mitchell and Jessen's techniques produced no useful intelligence. They were paid $81 million for their work.