Looking for any trace of recreational drugs, in hopes that they may be able to influence the media, public, and possibly one day a jury in some way by painting the deceased as a "druggie".
Several years ago some "bounty hunters" broke into a home in this area in the middle of the night and shot to death a young couple in their own bed. (As so often happens, they were looking for someone who didn't even live there.) The minute autopsies on the victims revealed marijuana use, every news story about the incident began leading with that - the fact that the murdered couple were "drug-users" - as though it somehow made the individuals who killed them less culpable, and their deaths less important.