http://www.sciencemag.org/news/2018/06/nasa-rover-hits-organic-pay-dirt-mars

A mudstone drill site called Mojave on Mars was one of two yielding organic molecules resembling kerogen.

In its quest to find molecules that could point to life on Mars, NASA's Curiosity rover has struck a gusher. Since Curiosity landed in 2012, it has sifted samples of soil and ground-up rock for signs of organic molecules—the complex carbon chains that on Earth form the building blocks of life. Past detections have been so faint that they could be just contamination. Now, samples taken from two different drill sites on an ancient lakebed have yielded complex organic macromolecules that look strikingly similar to the goopy fossilized building blocks of oil and gas on Earth. At a few dozen parts per million, the detected levels are 100 times higher than previous finds.