Are criminals rational decision makers, or are most of them motivated by uncontrollable psychological and emotional drives or social forces such as poverty and despair?

Some criminals are rational. Some are driven by psychological and emotional factors. Some are a combination. There is no single source of motivation that drives all criminals. Let us look, for example, at a young man from a very poor neighborhood who becomes a drug dealer and perhaps an occasional thief or mugger. He may be acting in part rationally. He may believe that he has needs that he wants to fullfill

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab.