Are unexplained methane spikes proof of life on Mars?

Are unexplained methane spikes proof of life on Mars? | Daily Mail Online: "In the past few months, conclusive evidence has been found that Mars once had water on its surface, but one greater question remains: Was there, or is there still, life on Mars as well? Scientists may be on the brink of answering that question with an equally conclusive 'yes', as convincing evidence has been detected by Nasa's Curiosity rover. An instrument on the rover identified spikes of methane that scientists believe may have come from bacteria-like organisms on the surface - and it could be the first alien life ever detected."