Power
Forensic scientists have the power to solve mysteries. Sure, maybe not the "what's the meaning of life" or "are we alone in the universe"-type mysteries, but they do get to work on the practical ones. The ones that end in justice served. The ones that can bring peace of mind to a victim's family or lock up a criminal before she kills a second time.
You're not alone in solving these crimes, of course. There are the other scientists, cops, lawyers, judges, and about ninety others we're surely forgetting here, but you're a crucial cog in a powerful machine. Just make sure you don't misplace any evidence along the way—your bosses won't take too kindly to mistakes like that.