Just out of curiosity, and because they have nothing to lose.... the lead investigator on the case tells the coroner to do a chromosone count and a DNA test, but to keep it quiet, just between the two of them so that no one would think they were crazy....
on another day, the coroner would show the investigator that the victem had a LARGER chromosone count than a normal human being is supposed to have.....
The investigator could say that it doesn't prove anything.... to which the coroner, maybe a member of CSI, depending where the movie takes place, would show him in a microscope, some sort of virus that he extracted from the gums of the dead person. This virus is larger than any he has seen, and contains the ENTIRE dna sequence of a certain animal....
I leave the rest to your imaginations.... unless you would like me to add more "details"
