For years while I was investigating the phone-hacking scandal at Rupert Murdoch’s London tabloid News of the World, I reckoned Will Lewis was not a criminal.

Long before he was knighted by Boris Johnson, promoted by Murdoch to run The Wall Street Journal, and then poached by Jeff Bezos to become publisher of The Washington Post, Lewis was general manager of Murdoch’s U.K. company.

I had written dozens of stories about the scandal for The Guardian before his name even surfaced. It was in the summer of 2011, when we disclosed that the News of the World had hacked into the voicemail of a 13-year-old murder victim, Milly Dowler, that Lewis stepped forward as one of the good guys, claiming that he would “drain the swamp,” helping the police to uncover the catalogue of crimes committed by journalists in search of stories to please their master.

A senior News Corp technician was ordered to destroy the backups of 30.1 million company e-mails.

The first doubt about Lewis’s innocence came a couple of years later, in the winter of 2013, at London’s Central Criminal Court, “the Old Bailey.” In the dock were Murdoch’s former editor Andy Coulson, who had risen to become the right-hand man of then prime minister David Cameron; another former editor, Rebekah Brooks, who had risen to become chief executive of Murdoch’s U.K. company; and a group of senior journalists from the News of the World.

They were charged variously with hacking the voicemail accounts of politicians, athletes, and entertainers, and paying bribes to police officers. Coulson and most of the journalists were convicted and jailed for hacking; Brooks was cleared.

During the trial, it was revealed that Brooks and Lewis had been involved in destroying almost all of the company’s e-mail archive before the police were able to access it. That looked very suspicious, but Murdoch’s company insisted that it had been done for entirely innocent technical reasons. There was no evidence to disprove this, and, in the detail, Lewis once again emerged as the good guy who had instructed the I.T. department to save the e-mails of suspect journalists from destruction so that they could be handed to police.

Rupert Murdoch with Will Lewis in 2011.

While Lewis rose to new heights of prestige and power, more than 1,200 victims of the phone hacking sued Murdoch’s company, and as their cases slowly worked their way through the London courts, judges ordered the company to hand over more and more internal documents.

As I show in the revised edition of my book, that material undermined the company’s defense, suggesting that Brooks and Lewis may have destroyed the e-mail archive with the specific intention of concealing the company’s history of crime.

Last year, The New York Times and NPR reported that Lewis had tried—unsuccessfully—to stop The Washington Post from running stories about the deleted e-mails. Allegedly, The Washington Post’s executive editor Sally Buzbee chose to resign after Lewis pressured her to avoid covering the news. Since then, still more damning evidence has emerged, including in the case brought earlier this year by Prince Harry.

In the course of preparing a new edition of my 2014 book, about the scandal, I looked at hundreds of pieces of evidence disclosed in thousands of pages of legal paperwork, and it seems to me that there is now an overwhelming case that Lewis was centrally involved in destroying material that likely would have been important evidence in the criminal and civil cases. Under U.K. law, that makes him potentially guilty of perverting the course of justice, which carries a maximum sentence of life in prison.

It’s a complicated tale, and I’ve laid out all the detail in the new edition, but there are some simple points which even in isolation are clearly troubling.

Roughly a decade’s worth of old e-mails, covering years of illegal activities by multiple private investigators working for Murdoch titles, was destroyed in September 2010—after the first victims of those crimes had formally requested that the evidence be preserved.

Three more potentially crucial years of the archive were destroyed four months later, even though Scotland Yard, too, had now begun asking for evidence. One of those years was destroyed on the explicit instructions of Lewis, citing the approval of a company lawyer.

Originally, the company was able to justify this destruction of 30.1 million e-mails by saying that they had kept backups. That was true. But now we know that after Scotland Yard began investigating, a senior News Corp technician was ordered to destroy the backups. And he did.

Former News of the World editor Rebekah Brooks, seen here at the Old Bailey in 2014, was cleared of all charges.

It’s true that Lewis saved the e-mails of suspect journalists from destruction and had them stored on a laptop. But that laptop was never given to the police. Detectives eventually found it in a safe, which was hidden under a section of floor, which was itself hidden under a vanity unit in an annex to Brooks’s office.

It’s true that millions of messages had been deleted from the archive for legitimate reasons. But Brooks’s own e-mails were not kept in that archive. She stored them on her own computers. Yet, shortly before the police moved in, her messages, too, were removed—and never seen again.

E-mails were not the only material to disappear. In October 2010, nine boxes of paperwork and audio tapes were removed from the paper’s newsroom. Months later, when police searched the premises, they set aside 125 office storage units for further inspection.

Lewis and a colleague were responsible for the security of the area where they were kept. According to court documents, eight filing cabinets full of paperwork belonging to senior editors then went missing before detectives could review their contents.

It’s true that Lewis stepped forward to help police and that he was accepted as a trusted contact. But now the officer who led the inquiry, Deputy Assistant Commissioner Sue Akers, and one of the detectives who was most closely involved, Detective Inspector Barney Ratcliffe, have both made sworn statements that if at that time they had seen the evidence that has since emerged, they would have viewed him as a suspect. D. I. Ratcliffe says he would have considered arresting Lewis for perverting the course of justice and obstructing police.

It needs to be said that lawyers for Murdoch’s U.K. company, which is still led by Rebekah Brooks, dispute almost every step in my argument, pointing out that, in December 2015, British prosecutors said that there was no evidence that e-mails had been deleted in order to pervert the course of justice. It is not clear whether they did not have access to all the new evidence or whether they saw it all and came to a conclusion that is hard to understand.

Lewis himself has disputed nothing. I sent him a list of detailed allegations, followed by three more e-mails asking for comment. Eventually, his office acknowledged receipt but declined to say anything in his defense.

Hack Attack: The Full Story of the Phone-Hacking Scandal will be published by Vintage on September 4

Nick Davies is veteran investigative journalist. The recipient of numerous awards, he uncovered the phone-hacking scandal for The Guardian