Juan Vucetich made the first criminal fingerprint identification in 1892 in Argentina.. [http://onin.com/fp/fphistory.html]
You gather and process evidence and testimony.
you have to have a detective or do it yourself.
the lip print is a print you make with your lips by wiping your lips with a napkin or kissing somebody it is your mouths signature
By looking for clues, duh.