Barry DiGregorio, an honorary research fellow at the University of Buckingham who specializes in studies of microscopic life found in soil, said recently that imprints found in rocks by NASA's Curiosity Mars Rover last month could represent trace fossils left by previous life forms. Trace fossils are created from indirect evidence of life, like footprints and fecal matter, as opposed to skeletons or similar bodily remains.

In this case, the potential trace fossils are tiny indentations that DiGregorio claims could be signs of "soft-bodied creatures" that once lived on Mars.

NASA has stated that the marks are a result of crystal growth similar to the formation of gypsum crystals, but DiGregorio accused the space agency of using this explanation as part of a cover-up.

"Put it this way, these images, these figures, have not been seen on Mars to date," DiGregorio said in an interview with the Daily Star.

"One of the things that grabbed me immediately was the expediency that NASA left the area of such a mission. So when I started looking, it wasn't just the objects that were attached the outside, what they are calling sticks. If you look at the images more closely, the sticks merge into the host rock, this actually has features in it that are reminiscent of trace fossils. NASA has turned its back on trying to get the data on this. The order came down from NASA HQ that they should move the rover on to the next point. They didn't feel it was important enough to look at, I thought that was very odd, despite the fact a gale crater was host to probably a series of lakes for billions and billions of years. Crystals don't add up. Crystals don't branch or twist. We're talking about something that might have been equivalent to the Ordovician period on Earth."

DiGregorio said that he plans to work with two other experts to examine the findings, and release a report that will argue in favor of an extraterrestrial hypothesis.

"At this time I'm working with two other experts, and we're going to prepare a paper, I'm not the only one looking at these things," he said. "Well we're going to look at it, and basically a good scientist presents a case."

He further alleged that NASA has a vested interest in denying the possibility that life exists on Mars.

"If you have been in this as long as I have, to have seen all the things I have seen, with NASA, I would actually say that they are avoiding looking for life," DiGregorio said.

"And that is, if they know that there is life there, and I very truly believe that NASA knows that there is living microbes in the soil of Mars. If they announced that, once that has been satisfied to the general public, people who pay their taxes to send the $2.5 billion probe to Mars, they are going to say okay well we discovered life, we don't need to go there anymore."

DiGregorio has previously published two books positing evidence of life on Mars; Mars: The Living Planet (1997), and The Microbes of Mars (2011).