What happened? A corpse is discovered in an enclosed room, there are no open windows, yet blowfly larva (stage 2) are found on the body. What does this tell you about the corpse?

The corpse was deposited into the room from somewhere else

Explanation:

The larva could not have spontaneously emerged from the corpse if the blowfly had not somehow perched and laid its egg on it. Since there are no open windows, and perhaps, other openings to the room; the only plausible explanation for the emergence of the blowfly larva would be that the corpse was deposited into the room from somewhere else. From the initial location, the blowfly had perched and laid its egg on the body and the eggs only hatched while in the enclosed room.