What is the difference in a forensic detective and a forensic scientist?

A Forensic Scientist and A Csi Forensic scientist are the same there is no change in what you do. The only change is where you work.

The title of "forensic scientist" is a more general label, while forensic biologists focus specifically on living forensics. I would guess that forensic biology falls under the umbrella of forensic...

No one studies it and the other detects it...

Forensic science is used to describe all categories of science in the legal system. forensic technicians are in a certain category within forensic science.