There are certain times in the dialogue when you can show the suspect evidence to disprove what they are saying. If you do this enough times you win. You can tell when to present evidence by the suspect starting to sweat. So when that happens pay attention to what they are saying and present the evidence you think disproves that. You can present evidence by dragging it forward off the table. And you can used W and S to look down at the table then back up. Hopefully that helps, thanks for giving it a try!