I think the police version is the most likely one, and Simon the most plausible suspect.

"So you were a plausible suspect," Blake said.

Though the tactics instructors had known there were only two plausible suspects and had started them both on a month-long, highly personalized calisthenics program.

A 'plausible' suspect, you mean?

But the abundance of conspiracy theories have yet to find a particularly plausible suspect.

Someone, that is, besides the screenwriter, Sarah Thorp, who supplies an abundance of psychological back story to make Jessica both a plausible suspect and a sympathetic figure.

Pippa was a less plausible suspect, but possible.

Mr. Cotton was a plausible suspect.

He was a plausible suspect.

There were only two people who could have written this, and of the two, Mr. Mitnick was the only plausible suspect.