What would go in to make a good murder thriller novel? A murder (or murders) has been (or is going to be) committed. There is a suspect; somebody with the job. The suspect is anonymous. The detective has to find the killer.
The detective could be a professional or someone who has been brought in the murder through the circumstances. In Frederick Forsyth’s ‘The Day of the Jackal’, the detective is a professional. The best French detective has to find a man who is going to kill the President of France. He has no idea of who this man could be, how and when the killing will happen or even that a job of such nature is on hand. Information in a good crime thriller novel should be revealed like the melting of ice, slow and uniform until the waters are clear for the reader. Giving too much information at the start would kill interest and giving too less would make the story redundant. Mystery is wedded to information in a zero sum game. More information implies less mystery and vice versa. The Jackal, whom you will fall in love with, never reveals more than he has to.
It is not necessary for the novel to have a structure like the one above. In John le Carre’s classic ‘The Spy who came in from the cold’, there are no clear boundaries between the killer and the detective. The narrative is finely layered and onus of crime well distributed on both parties (in cold war era, espionage was at its peak. Both sides did it.) Both novels have a thing in common. Somebody is out there to make a killing. Somebody else is out there to prevent it. And the reader is hooked to the story to know whether or not it will be done.
What if a murder has already been committed? Something like a serial killer is on the prowl. Time is an important factor here. The detective not only has to find the killer but also prevent the next murder. One is reminded of Seven (later made into a movie starring Brad Pitt and Morgan Freeman). Or it could be a one-time murder many of which Byomkesh Bakshi or Sherlock Holmes have solved. But this knowledge that the murderer is about to make another kill can help finding him/her, if the motives can be found out.
Establishing a motive is important. Mostly it could come from a historical enmity or psychology. The process of killing is also essential to give clues to the detective. A good murderer never leaves clues or leaves them to confuse. If two Professors, one in Gujarat and another in Jharkhand are killed, what can a young Economics Professor and a journalist do to find the murderer when everybody else is sure that it is suicide? They have to get to the motive and find the process of killing. And what if nobody else has ever used the weapon used in these murders? It makes their job a little more difficult.