A prison officer has been paid thousands of pounds for information by News International, Trinity Mirror, and Express and Star Newspapers, the Leveson Inquiry has heard.DAC Sue Akers, the Metropolitan Police officer leading investigations into alleged criminality by the press, said today the prison officer had allegedly been paid a total of £35,000 by the newspaper publishers between April 2010 and June 2011. Payments had been transferred into the officer's partner’s bank account.The prison officer retired in June 2011 but apparently received a final payment from Express Newspapers - publisher of the Star and Daily Express - in February this year.The discovery – alongside another revelation that Trinity Mirror allegedly paid another prison officer at high security prison £14,000 between February 2006 to January 2012 – means a probe into illegal payments has been launched at Trinity Mirror and Express Newspapers, according to Akers.She said the Met had found four stories published in the Daily Mirror, which were believed to refer to information provided by the second officer. The force served notices to the legal departments of Trinity Mirror and Express Newspapers. Akers said Trinity Mirror asked for a production order while Express Newspapers were drawing up a voluntary protocol.She told the inquiry: “In our assessment, there are reasonable grounds to suspect that offences have been committed and that the majority of these stories reveal very limited material of genuine public interest.”Akers said the Met believed some News International material was taken from stolen mobile phones and were working to find out whether the Operation Tuleta investigation has uncovered isolated incidents or “just the tip of the iceberg”.One of the phones was stolen in Manchester and another in London. The Met will continue to analyse eight to 12 terabytes of data on 70 storage devices in relation to Tuleta – examining alleged phone hacking, computer hacking and the obtaining of personal records by the press. There are currently 101 individual claims relating to the investigation.Six people have been arrested under the Computer Misuse Act or on suspicion of handling stolen goods, and are currently on police bail.To date, 41 people have been arrested under Operation Elveden – the investigation into payment of public officials by journalists – 23 current or former journalists, four police officers, nine current or former public officials and five other people who allegedly acted as conduits for payments.Akers said the Met had completed identifying and notifying hacking victims – a total of 4,775 potential victims, of which 2,615 were notified, with 702 individuals “likely” to have had voicemails intercepted. Akers said the figure of "likely" victims had been higher (1,081), but the force were unable to contact all of them.Fifteen current and former journalists have been arrested and interviewed in relation to phone hacking. Twelve of those remain on pre-charge bail, 11 of whom are due to return to various police stations tomorrow. One individual has been bailed to August 2. One non-journalist has also been bailed to tomorrow.Akers told the inquiry Will Lewis and Simon Greenberg, of News International's management and standards committee, no longer attend regular meetings with the Met. She said the MSC had stopped disclosing information to the police from the middle of May until June 13.She said there was a "change in the nature of the cooperation" between the MSC and police officers after the arrests of Sun journalists earlier this year but said the committee had provided a lot of evidence of "suspected criminality".The deputy assistant commissioner agreed to provide Lord Justice Leveson with an update on Elveden, Tuleta and phone hacking investigation Operation Weeting in the autumn.