Wishful thinking, if you were to ask The Economist’s “Babbage”. He links the briefings editor’s blog, Mainly Martian:

…thousands of tonnes of organic material arrive at the surface of Mars every year. Once it gets there, it either has to be got rid of or it accumulates. Recent work has also shown that most of the Martian meteorites studied have been found to contain organics that were aparently created on Mars through means that have no link to biology (Science paper here). So not only should people presume there are at least some organics on Mars—people have actually found and studied organics from Mars.

Let’s keep on searching then.