I also need to know the major crimes used by fbi

Look below here, on this page, you will see a section called, "similar questions" - look through those. The question has been asked often enough.

What do you mean by "major crimes used by the FBI"? Do you mean what kinds of major crimes they work to solve or assist in solving? Google it.
Federal Bureau of Investigation - Major Thefts and Violent Crimes (http://www.fbi.gov/hq/majorthefts/majorthefts.htm)