MrBIGG, I'm think you're referring to the controversy about the meteorite designated 'ALH 84001'
Here's a link that deals with that:
http://www.lpi.usra.edu/lpi/meteorites/life.htmlFrom the link:
"To summarize, the Science paper of McKay and co-workers leaves many unanswered question. As they forthrightly state, their paper is NOT PROOF OF LIFE ON MARS. Their paper presents evidence that, on its surface, is consistent with ancient life on Mars; McKay and co-workers believe that the evidence is more consistent with life on Mars than any other explanation or explanations. Almost all of their conclusions can be disputed and will likely be disputed.
From my perspective, their strongest conclusion is that ALH 84001 contains polycyclic aromatic hydrocarbons (PAHs) that formed on Mars. These PAH molecules may be related to martian micro-organisms, as McKay and co-workers suggest. The PAHs might also have formed without assistance from living organisms, in what might be called a prebiotic organic chemistry. Proof of a prebiotic organic chemistry system in Mars would be nearly as exciting as proof of life itself."
Allan H. Treiman, Lunar and Planetary Institute [NASA-funded]
August 21, 1996
To sum up: There's no proof that there is, or has ever been, life on Mars.