If there was ever life on Mars then the chances are good that there is still some level of life still there. On our planet, there is life in every unimaginable place. You have shrimp living in water that is boiling thousands of feet under the sea. The Great Salt Lake is infested with microbiological life. When you find an environment that you would swear could not possibly support life, a closer look finds it. The most unlikely of these creatures are called extreemophiles. High pressures, temperatures from sky-high to frozen, acid, and darkness all seem to have little ability to stifle life on Earth so I suspect that if at any point Mars was capable of supporting life and it arose that it still at some microbiologic level has survived. Just my humble opinion...
