Here's a complete list of job openings at the FBI. Take a look and you'll see there are a lot of jobs other than the position of a special agent. In fact, while agents are the stars of the FBI, they're not the highest paid employees. Special agents start at around $57,000 but if you have skills and knowledge in speaking foreign languages or in computers you can make significantly more. There's an opening for an archivist supervisor that pays about $120,000 a year.
I checked the list and didn't find any openings in St. Louis. But if you have the right skills and a willingness to move, there are some good paying jobs available at the FBI. Check it out.