Andy Coulson arrested on Suspicion of Perjury

The transcript details a police investigation involving a former News of the World editor, who was questioned about his testimony in a perjury trial related to phone hacking. The investigation aims to determine if he lied during the trial. Public statements suggest a belief in overturning a previous conviction. The focus is now on Downing Street's former communications director.

What does the individual believe marks the beginning of a journey regarding their conviction?

Who is now the focus of the police investigation according to the text?