How to develop characters in a crime novel

I develop my characters using spider grams. I draw a circle and put each character in the centre of that circle and then I throw out lines and ask a series of ‘open’ questions about each of them. For example, if I have the victim in the circle then I’d ask questions such as who is he? How did he get where he is? Why would someone want to kill him? Who killed him? How was he killed? What’s his background, family, education, experience? What’s his occupation? How old is he? Where does he live? What’s his personality? What does he look like? What has shaped him? How are the victim’s family, friends and others going to react? How do they see this character? What’s my main character going to do next?

I draw up character profiles for each of the main and secondary characters, some might be sketchier than others. But that doesn’t matter because it isn’t until I start putting dialogue into their mouths and have them walking around and interacting with people that they come alive. Until then they are just notes on a piece of paper. But those notes can be added to as my characters start to take shape through my writing.

The characters’ actions drive the plot. The surprises, twists and turns all spring from the characters' motivations and as I write I find ideas occurring to me that I hadn’t previously considered. I sometimes discover that someone I thought was going to be a minor character turns out to be much more interesting when I write his part, and a major character becomes boring and sometimes unnecessary, if that happens then I cut him out.