prime suspect
main suspect

Should he have been left off a list of prime suspects?

"He certainly is the prime suspect, and I'm working with the state police on the case."

But when asked if the company was the prime suspect, he said yes.

"So allow me to do my job as prime suspect and say nothing else, all right?"

They know it isn't when the other prime suspects are at large.

His wife and brother begin to fall in love, despite the fact that he has become the prime suspect.

To make things easy for them, there's a prime suspect.

And he's got to be a prime suspect in all this.

The prime suspect will eventually turn out to be a white man.

Now then, are there any prime suspects in your mind?