criminologist:
(plural: ‘criminologists‘; pronunciation: the letter ‘c’ in this word is pronounced with a ‘k’ sound — for the right pronunciation, please click here)

a female criminologist
a person who studies criminals and crimes scientifically, usually such matters as why people do bad things, what kind of bad or illegal things people often do, what kind of people do what kind of crimes, what possible steps can be taken by the law to change criminal minds from doing crimes, etc.;
an educated person who is a specialist in criminology, i.e. who studies and so knows about crimes and criminals and gives advice to the police and law & order departments on how to deal with criminals,
A criminologist is an important person in solving or preventing crimes because he/she studies crimes and understands the minds of criminals, therefore, can help the law and order departments in assessing a criminal or in avoiding a crime.
After completion of his/her degree, a criminologist may find a job at a law university teaching criminology, sociology, etc. or find a job in police department or prison department, or even engaged by big companies on security issues to control or prevent criminals attacking their companies, or work as an adviser to some international security agencies, such as CIA of the USA, Interpol, etc., in assessing terrorists, smugglers, insurgents, etc.
Most criminologists are law and sociology graduates who act as counsellors to the prisoners to bring in psychological changes in them.

