There are many types, just as there are many types of crimes, CAPERS (Crimes Against Persons), Crimes Against Children, Property Crimes (thefts, burglaries, Criminal Mischief), Fraud, Auto Theft, Drug, Mortgage Fraud, etc. Many agencies start their new investigators in property crimes, where you will develop your investigative skills, attend training classes, etc. It's important to remember that if you are starting out in the patrol division, you are really the first investigator at the scene. Actions you take, observations you make can be critical. Best Regards.