The FBI has many types of technology. The most common would probably be D.N.A.. Some more you are probably unaware of would be C.O.D.I.S.
There are many other technologies that we are unaware of which I will not
emphasize on but you can look it up at fbi.gov.

DNA nowadays can:
...Establish both guilt and innocence;
...Link together seemingly unrelated cases (including serial crimes) so they can be investigated in tandem;
...Act as a set of "genetic fingerprints" that can positively identify not only criminals and terrorists, but also the remains of victims and missing persons, often years later;
...Keep dangerous felons behind bars by connecting them to other offenses;
...Quickly eliminate suspects and speed up investigations; and
...Bring closure and peace of mind to victims and their families by solving otherwise unsolvable crimes.