Life
  Definition of Life
  Fossils
  Martian Meteorite

Data Analysis
  Thin Section Analysis
  Isotope Analysis
  Gas Chromatograph Mass Spectrometer
  Infrared Spectroscopy
  Alpha-Proton X-Ray Spectrometer
  Detection of Carbon Complexes
  Labeled Release
  Gas Exchange
  Pyrolytic Release
  Stimulus Response Experiments

In the meteorite Allan Hills 84001, scientists found structures that they believed could be fossils of ancient microorganisms as well as organic compounds. Now that result appears inconclusive, or possibly false, because the same hydrocarbon evidence can be produced by abiotic processes (Golden et al., 2000). It is even possible that that terrestrial bacteria have contaminated the meteorite, making any confident statement about extra-terrestrial life questionable (Steele et al., 2000). However it must reiterated that the possibility that the rock contains fossils has not been eliminated. The possibility of life on Mars will not be ruled out even if this meteorite is proven to not have life. 

Sources
Golden D.C., Ming D.W., Schwandt C.S., Morris R.V., Yang S.V., and Lofgren G.E. "An experimental study on kinetically-driven precipitation of Ca-Mg-Fe carbonates from solution: Implications for the low temperature formation of carbonates in Martian meteorite ALH84001." Meteoritics and Planetary Science, 2000. vol. 35, 457-465.

Steele A., Goddard D.T., Stapleton D., Toporski J.K.W., Peters V., Bassinger V., Sharples G., Wynn-Williams D.D., and McKay D.S. "Investigations into an unknown organism on the Martian meteorite Allan Hills 84001" Meteoritics and Planetary Science, 2000. vol. 35, 273 - 241.