There are reports that News International found emails in 2007 that appeared to indicate that more than a single journalist was involved in phone hacking, and that payments were being made to certain police officers for information.
However, the alleged evidence of criminal behaviour was not handed over to police until last month by the company, which owns the News of the World.
News Corporation chairman Rupert Murdoch today visited the newspaper's offices in London.
The 80-year-old was seen holding a copy of the final edition of the axed News of the World as he was driven into News International's headquarters.
It is thought Mr Murdoch is meeting News International chief executive Rebekah Brooks at another location.
News International declined to comment on reports that the Metropolitan Police were handed internal memos from 2007 that appear to acknowledge payments were made to police for information and that the practice of phone hacking was more widespread than previously thought.
Mr Murdoch said yesterday that it had been a 'collective' decision to close the tabloid.
He also renewed his backing for Ms Brooks - who edited the paper at the time of Milly Dowler's disappearance - despite widespread calls for her to go.
Ms Brooks has remained defiant as the scandal engulfing the tabloid gathered pace in recent weeks.
Resisting calls for her resignation, she has told British MPs she had ‘no knowledge whatsoever’ of claims that murdered schoolgirl Milly Dowler was among up to 4,000 people who might have fallen victim to hacking.
And she insisted there was ‘no reason to believe’ that hacking had been used by any other News International titles.
The final edition of Britain's biggest-selling Sunday newspaper rolled off the presses for the last time last night.
The headline on the front page simply reads 'Thank You & Goodbye'.
The Irish edition of the paper employed 22 full-time and ten part-time staff.
The overall print run was doubled to five million copies, with money from the sales being donated to four charities.
A sub-headline in the 8,674th edition of the tabloid reads: ‘After 168 years, we finally say a sad but very proud farewell to our 7.5m loyal readers.’
And in the top right corner are the words: ‘The world's greatest newspaper 1843-2011.’
The closing issue features much celebration of the best scoops and greatest campaigns that have helped the newspaper make its mark over the years.
But there is also an apology for the phone hacking scandal that eventually brought the tabloid to its knees.
The statement, printed on page three, reads: ‘We praised high standards, we demanded high standards but, as we are now only too painfully aware, for a period of a few years up to 2006 some who worked for us, or in our name, fell shamefully short of those standards.
‘Quite simply, we lost our way. Phones were hacked, and for that this newspaper is truly sorry.’
Dowler family to meet Cameron
The family of Milly Dowler are to meet British Prime Minister David Cameron tomorrow to discuss his government's response to the phone hacking scandal.
Milly's parents, Bob and Sally Dowler, are suing the News of the World over claims their daughter's phone was hacked when she went missing in 2002.
As the paper was finally put to bed, the criminal investigation into alleged illegal practices continued to gather momentum with officers poised to make more arrests.
In the last three days, three people have been questioned by police.
A 63-year-old man arrested in Surrey on Friday in connection with alleged corrupt payments made to police officers, has been bailed to return to a London police station in October. Officers would not confirm reports that he is a private investigator.
Former News of the World editor Andy Coulson was questioned for nine hours on Friday over suspected corruption and the scandal which forced the paper's closure.
And ex-royal editor Clive Goodman, 53, has also spoken to police over claims officers were bribed following a dawn swoop on his Surrey home.
Mr Cameron is also likely to face further scrutiny over his decision to retain Mr Coulson as his spin chief on coming to power.
Former Liberal Democrat leader Paddy Ashdown said he had warned Downing Street it would be a ‘disaster’ shortly after the general election.
Miliband seeks to block BSkyB takeover
Labour Party leader Ed Miliband has said his party will force a vote in parliament to try to stop News International's bid to take full ownership of BSkyB until criminal investigations are complete.
News International, which is owned by Rupert Murdoch, is attempting to gain complete control of the broadcaster which owns Sky News.