http://www.newsweek.com/mars-nasa-destroyed-organic-matter-1021155

A new analysis of 40-year-old data found that NASA exploratory spacecraft might have detected evidence of life on Mars decades before the June discovery of organic matter on the Red Planet—but the results were likely destroyed before they made it to Earth.

The 1976 Viking landers were sent to Mars in search of organic matter but returned with nothing. In reexamining the Viking mission’s data, researchers identified chlorobenzene, a chlorinated organic material created in a reaction with the salt found in Martian soil, according to findings published in the Journal of Geophysical Research: Planets.