Did we miss life on Mars?

There is no proof the 1976 Viking landers missed finding life on Mars. There is, however, an intriguing new theory about how they could have.
Geology professor Dirk Schulze-Makuch has published a paper suggesting that the VIking experiments could actually have killed life isntead of finding it. By adding water to Martian soil and then warming it - a logical way to look for Earth-type microbes - Schulze-Makuch suggests the experiments may have drowned and/or baked life forms with significantly different chemistry.
In the cells of Earth-based life forms, the basic internal liquid is some variant of salt water. On the cold, dry Red Planet, a mix of water and hydrogen peroxide may have evolved instead. Astrobiologist Mitch Sogin, a member of a National Research Council committee on alien life, said, "I'm open to the possibility that it could be the case." Future probes carrying more sophisticated experiments may settle the question.