(CNN) - There's a potential new lead in the search for missing Malaysian Airline 370.
CNN has learned a sound - that could have been the plane crashing - was detected by underwater microphones. The United Nations Nuclear Test Ban Organization has a network of 11 hydrophone stations that pick up many sounds, even ice breaking thousands of miles away in Antarctica.
But Wednesday, there was a huge setback in the search for Flight 370. US Navy leaders say those underwater pings detected during the search did not come from the missing plane. Now the Navy says the sounds could have been from the search ship itself or other electronics.