Red rain came from Mars via comet.

Wikipedia article http://en.wikipedia.org/wiki/Red_rain_in_Kerala
describes red rainfalls that occurred in 2001 in Kerala, India.

I found numerous mammalian red blood cell fossils in the following
micrographs of the red rain particles:
http://www.wretch.cc/album/show.php?i=lin440315&b=28&f=1177197612&p=204
http://www.wretch.cc/album/show.php?i=lin440315&b=28&f=1177179751&p=205
http://www.wretch.cc/album/show.php?i=lin440315&b=28&f=1177191075&p=206

Only mammals possess this unique kind of red blood cells. Since Mars
and Earth are the only two planets in our solar system that have ever
been inhabited by mammals, the red rain in Kerala, India should have
originated from Mars via a comet.