While discussing the results of Curiosity's highly anticipated soil tests at a press conference today, NASA revealed that the rover did in fact discover evidence of organic compounds. However, NASA has not yet determined the source of the oxygen and chlorine compound perchlorate — Curiosity may have brought the organic carbon from Earth. If NASA does rule out the possibility that it was brought from Earth, another analysis is required to determine if the perchlorate originated on Mars, and yet another to find out if the carbon is actually biological.
In addition to being the first soil analysis to make use of all of the rover's instruments, principal Curiosity investigator John Grotzinger explained that the test served the dual purpose of cleaning the instruments of possible carbons brought from Earth. He described the complex rover as a "car that comes with a ten thousand page user manual that we also have to write as we read it," but added that because of these tests "we've learned a whole lot more about [Mars] than we knew before." NASA will continue to work to determine of the carbons Curiosity detected are indigenous to Mars, and will conduct a drilling test before the rover travels to Mount Sharp early next year.