There have been two other missions, including this one by the ESA, that have detected far higher amounts of methane in the Martian atmosphere than was detected in this experiment:
http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Mars_Express_confirms_methane_in_the_Martian_atmosphere
I think a more likely explanation for such an incredibly low result, on a world with known geologic activity that should be producing some methane, in contradiction to earlier experiments, is that the detector is broken.

I'm surprised the bookies haven't gotten in on this one.

So how can they check that the instrument(s) has/have not failed?
It seems rather odd that previous forms of observation have indicated that there is methane on Mars yet Curiosity seems to see absolutely none at all, even when some was expected.

I think the detector is borked... See here: www.gizmag.com/methane-life-mars/13578

Who is to say that the form of life on another planet must involve Methane? Is this a universal constant throughout the galaxy?

"Despite this setback, it doesn't mean that the search for life is over." Sadly, junk science will continue! A little set back will not deter the faithful in their quest to discredit the true origin of life.

There doesn't have to be any current life on Mars. There may be fossilized evidence of life from prior epoch's. We really won't know much about it until we get there and stay and have scientists there permanently. Which would be better a lot sooner than later.

"Sadly, junk science will continue! A little set back will not deter the faithful in their quest to discredit the true origin of life."
I don't get it. If you're talking about religion, I still don't even understand what finding life on other planets has to do with discrediting anything. Finding microbes on Mars would be essentially the same as finding bacteria on an island here on Earth previously thought to be barren. There's life all around us. Some of it is even intelligent. That doesn't discredit God, or contradict the idea that he created life, unless you believe that Mars is beyond his reach or something.

Have to agree with Desann. It does not in any way discredit God. Read your Genisis a bit more. "In the beginning God created the heavens and the earth. The earth was formless and void, and darkness was over the surface of the deep". It is the heavens and the earth not just the third rock from the sun. And personally I find it amazing that when you look at the skies or the images of Hubble and other than any one can not see the wonder in it. Some just see rocks and stars while other see beauty and wonder. I choose the later myself.
If God was not involved it was a hell of a good accidental mix ;-] Then I look at the platypus and wonder if God was either hung over bored or just wanted to mess with people.....

The article spoke of the quest to find life or the proof of any life at any time on Mars. Some believe that this was where life originated. How life got from Mars to the earth takes a HUGE leap of faith. The earth is the only planet where all the right ingredients and elements in their proper arrangements exist where life can be supported. To search for physical life outside of the earths realm takes a lot of what is called blind credulity.