Here's a question: can they carbon-date this matter? It would be interesting to determine the age of the matter. Unfortunately, we may not know enough at this time to be able to make an accurate determination. I'm not entirely certain that carbon dating is always accurate on Earth, much less on another planet. Also, there may not be enough matter on which to run any tests.
Wouldn't it be funny if the next memo is that it was accidental contamination from Earth?