Over the last four years, 20 to 40 percent of the honeybee colonies in the U.S. have mysteriously collapsed. The killer has remained unknown--until now. A team of entomologists, along with military scientists from the Department of Homeland Security, have a new prime suspect (or rather, suspects), as shown in a new report on the science website PLoS One. A tag-team of a virus and a fungus show every sign of being the culprit. Now it's just a matter of eradicating that dastardly partnership.